"You are welcome."
Translation:Je vous en prie.
You are both right and wrong, "De rien" is not the ideal translation for "You are welcome" and would indeed correspond to "It is nothing".
Still, however grammatically correct "Tu es la bienvenue" is, it is completely wrong in the context of the exercice which is is about learning common expressions and not making literal translations. In addition, the feminine gender comes out of nowhere and might mislead.
"Je vous en prie." or "Je t'en prie." is the correct answer.
De rien is the equivalent expression in French - it is correct in the test but see an incorrect translation above: "Tu es la bienvenue" is very literal and completely incorrect. In French communities in Atlantic Canada however, "Bienvenue" is commonly used to say "you're welcome" in French!
« De rien » literally means 'for nothing', it is used idiomatically as a contraction of the following exchange: « Merci. -- (Vous n'avez à me remercier) de rien », that is "Thank you. -- (Oh but you should thank me) for nothing" (ie. 'It is nothing').
« Tu es de rien » would be exactly the same as telling someone that they are 'for nothing', which you'll understand isn't acceptable. You should always keep the idiom « De rien. » (or sometimes, endearingly, « Mais de rien ! ») as its own statement.
This is why I wrote in my previous comment (2 years already!) that « De rien » is not an ideal translation. In my opinion, it is best left to analyse as a translation of "It's nothing", while "You are welcome" might more generically be translated as « Je vous/t'en prie » when one is learning French.
Also to recap on other posts in this thread:
« À votre service » is correct but more often used in the context of customer service, as MarySophieLe said. It is a higher level of language and therefore bears a higher risk of being interpreted as sarcasm, so I'd advise against using it in general.
Regarding « S'il vous plaît », yes! It is used in such a way in Belgium as well as parts of the north and east of France. It is highly specialised to those regions however, and people might not understand you properly in the rest of the country. Be careful!
I didn't know that the Québécois used « Tu es le/la bienvenu(e) » as a translation of the (figurative) expression. The French don't (ever), so for us « Tu es le/la bienvenu(e) » is always the literal translation -- as in "being welcome to come in". One less thing to worry about when learning Canadian French!
BTW, my dictionary states that bienvenu(e) can also be used as an adjective: opportune, apposite, or welcome as in etre le bienvenu, meaning that it is appreciated. The example they give goes like this: cet argent etait vraiment le bienvenu (that money was most welcome). I don't hear many people using the word "apposite" very much. I think it is used more for referring to grammar. I haven't heard bienvenu used this way, that I can remember anyway.
I had never seen the word 'apposite' before. Anyway, that is true and the expression is frequently used, I see it as an extension of its literal sense « être bien venu », very often with a hint of relief -- just like 'most welcome' in English, right? « Ces vacances seront les bienvenues ».
'Bienvenu(e)(s)' should be preceded by 'le/la/les' in that context, although people might sometimes mistakenly skip the article.
I can only think about it applied to inanimate objects or concepts and I don't believe you can use this meaning with a person, at least not in standard French. You can say « L'arrivée de Sabrina est vraiment la bienvenue ! » as a more formal way of saying "Thank God Sabrina's arriving!", it's fine although the present tense is a bit weird. But « Sabrina est la bienvenue ! » doesn't work in that way, it would create confusion as it already means that she is welcome. To come in. But not immediately. At least not necessarily. More her being generally happily received. Agghhhhhh!!!
In Belgium it is also used to mean "you're welcome" and "here you are"
I''ve heard people say, "Bienvenue," but the more complete way would be, "Sois la bienvenue" (familiar) and "Soyez la bienvenue" (formal). I think this is where some people get, "Tu es la bienvenue," because they see the infinitive, "Etre la bienvenue." Maybe they don't realize it's meant to be an imperative. I know people say things differently depending upon what country or region they come from.
I think mostly French people say to me, "je vous en prie." I always said "pas de quoi" (from "Il n'y a pas de quoi") or "de rien" and was always understood.
I'll give it a try at answering your question.
1) I'm unable to think of an instance where one would say, "You are welcome," like this in French ("Tu es de rien.") If you did say, "Tu es rien," it probably would be an insult.
2) I think you are trying to make literal, word for word translations, and you just can't do that when switching back and forth from one language from another, at least most of the time. English grammar and French grammar are so different, you just need to learn it and memorize. It helps if you can listen to native speakers on a daily basis of course. Also, you need to learn to think in French, and once you find yourself doing that, you will know you have a handle on it.
3) "De rien" means "not at all," "don't mention it," or like in English where we say, "No problem." I believe the literal meaning is, "it has no significance at all."
"Je vous en prie" is similar in thought. It is commonly used to say what would be in English, "You're welcome" in response to "thank you." Literally, it means "I beg you" in the context of "please." Example: "Je te prie de me pardoner." Please forgive me. In response to thank you, it would be like this: "Merci." Thank you. "Je vous en prie." (Please) don't mention it.
I like "Je vous en prie." I think it sounds pretty and cool too. I hope that helps.