Answer:
The answer to the question: ¿Dónde te vistes? is:
d. Me visto en la cabina.
Step-by-step explanation:
In a conversation, when somebody asks about you, the answer must have the personal noun "I", that's is the case of the question, where is discarded the option C because refers to "you".
The other options are eliminated because: the question is where but the A option is in the pool, a place where you can't dress and the option B says at seven, but that's an hour, not a place, by that reason is out too.