Are you supposed to correct the grammar?
If so, here's the answer:
Last summer, I went to France, because my aunt works there.
Your first option is correct.
EXPLANATION:
your first option is correct because this is a grammar question. When you use "an" you're using it in front of a vowel. The only sentence starting with a vowel is the first one. The others don't sound right when you use "an" in front of it instead of "a".
I hope I helped! :)
The words in the brackets are telling the actors what to physically do, meaning it would be a stage direction.
It isn't dialogue because that is a conversation between two people.
It isn't dialect because that is how a person speaks. There is no speaking in the brackets.
It isn't narration because it isn't spoken allowed for the audience.
It isn't a description because that is too broad a term more often used for emotions.
