The figurative meaning of "persona grata" in this context suggests that Callista has become a well-regarded and accepted figure among the student body due to her actions as the student council president. She is recognized and appreciated for her efforts to advocate for early release Fridays, indicating her influence and positive reception among peers.
None of the responses provided directly fit this explanation, but the closest interpretation might be:
Callista is being compared to a foreign leader in ancient times to describe her influence.
This response highlights her influence and acceptance, although it may not strictly apply to the original meaning of "persona grata."