"Rosa has a jacket."
Translation:عِنْد روزا جاكيت.
First, the sentence no. (1) عند روزا جاكيت means "Besides Rosa, there is a jacket" while the sentence no. (2) روزا لديها جاكيت simply means "Rosa has a jacket". Secondly, in no. (1), we put the emphasis on the adverbial place (at Rosa) while in no (2), we emphasize the subject (ie. Rosa). Also, the Arabic word for "jacket" in no. (2) is better because سترة is Arabic faSiHa.
So, we see that actually no. (2) is better to describe "Rosa has a jacket". But, it seems that the English translation for both sentences are the same, "ie. Rosa has a jacket". -- In short, no. (2) should be accepted as a correct answer.
Hope it is clear.
The order is عند ("at") => then روزا ("Rosa") and => then جاكيت ("a jacket). In Arabic, it is a nominal sentence. Literally, the sentence means "at Rosa a jacket" but Duolingo translates the sentence as "Rosa has a jacket" in English.
Hope it helps -- Hmm, I want to explain it further but I am afraid it would make the matter more complicated.
Nb: someone has given you a downvote for a legitimate question. But, I give you an upvote :))