Answer:
La hermanita de Marianela.
Step-by-step explanation:
You have to read the whole text and then, you have to answer the question that says "who is Rosa?". In English the text says the following:
Gabriel: Hi Marianela, what's up, how are you?
Marianela: All right and you? What do you do?
Gabriel: Nothing, I'm around here with the boys. And How is Rosa?
Marianela: Hey! She is my little sister. Very careful with her!
Gabriel: Me? Don't stain! Your little sister is very pretty but she is very small.
Marianela: Well, I just warn you, look it would be very bad if you hurt her.
Gabriel: Well, everything is cool. Friends?
Marianela: Friends.
Who is Rosa?
Marianela's friend
Gabriel's sister
Gabriel's girlfriend
Marianela's little sister
So as you can see, the text says that Rosa is Marianela's little sister.