Answer: “The music she plays is a powerful medicine that calms you instantly”
Explanation: Here music isn’t really medicine, but it describes it like it IS a medicine. So there you go.
using process of elimination you can eliminate condescending and pessimistic, and the passage doesn't really seem humorous either so your left with enthusiastic. The author seems to be happy and excited to share knowledge about how literature can make people feel, thus the best answer choice is probably enthusiastic