"You have yours."
Translation:Du har dine.
In English, the possessive pronoun changes as follows:
1st person: mine (singular), ours (plural)
2nd person: yours (singular), yours (plural)
3rd person: his/hers/its (singular), theirs (plural)
Note that for the 2nd person it looks the same for both singular and plural number. In Danish, this is not the case - they are different. And what you did in your sentence is you mixed up a plural subject ("you", like "y'all" or "you, guys") with a possessive pronoun declined as if you were talking to a single person.
Whether you should use dit or din depends on grammatical gender of the object you are talking about. In this sentence we do not know what that is, so both options should be accepted as an answer.
you have your apple => du har dit æble (because æble is neuter gender (et æble))
you have your orange => du har din appelsin (because appelsin is common gender (en appelsin))
Danish is one of many languages in which every noun is of one of a couple grammatical genders. Some of these languages have "masculine" and "feminine" genders, some of them also have "neuter". In Danish, every noun is either "neuter" or "common" gender. If you're altogether unfamiliar with the concept, I think this link may be useful.
You need to learn the gender of each noun by heart, together with the noun itself. Although, as a rule of thumb, inanimate objects usually are neuter, whereas people and animals etc. are common, but there are many exceptions to this.
The most obvious thing to check to determine a noun's gender should be its article:
et is the article for neuter nouns, e.g. et æble (indefinite) or æblet (definite)
en is the article for common nouns, e.g. en appelsin (indefinite) or appelsinen (definite)
Due to the article, neuter nouns are often called "t-words" and common nouns - "n-words".
It depends on the object of the discussion - its gender and grammatical number. For example, somebody says: "Give me your apple!". You may respond with a sentence like "Nope, du har dit!" - you ought to use "dit" because "apple" is neuter in Danish (et æble). Duolingo might accept either of the 3 options as a translation because there is no context here, but if there was, you'd need to choose the right one ("din" for common gender nouns, and "dine" for plurals).