Aunt which your mother's sister
also could be labeled as
aunt on the mothers side
"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?"
These are all the answers that could fill the blank: sell, market, and promote. Hope it helps and remember to mark as the brainliest answer!