"she" would be the pronoun.
You can rewrite this question as "She is your best friend?"
So in that case, "she" would be the subject.
In English, you just switch around "is" and the subject to make a question and make it sound Englishy
PS in Italian (and probably other languages) you would just say "She is your best friend?"
The protagonist would be Cinderella
Answer: you, your, you're, yours etc.
Explanation: Think of second person as the narrator speaking to you, the reader, and that you're the main character in the story. If it's not a story, it's like a cookbook, "You mix the flour with the butter" or like an instruction manual telling you how to put your new dresser together. I hope this helps!
Answer:
they wont be able to eat ice cream anymore
Explanation: