Choices in Music Class

I left class last week feeling confused about the conversation regarding a chorister's choice of voice part in choir. And then I was faced with a student's resistance in my music classroom early last week:

In the lesson, the students chose instruments on which to improvise and followed my conducting (and eventually their peers' conducting) to create their own music. I taped our performances and we critiqued them together. By the end of the class, everyone had an instrument and took part in the ensemble. Every student--except one-- was actively participating and seemed really to enjoy the experience. (This student is often resistant in music class, and in other classes, as I have discussed the problem with her homeroom teachers.) She refused to choose an instrument. Our conversation went like this:
Teacher: [Student], please go pick out an instrument.
Student: I don't want to.
Teacher: Why not?
Student: I just don't want to.
Teacher: It is part of class today that we're playing instruments together. Go pick out whichever one you want to play.
Student: No.
Teacher: (as a last resort) You do realize that your grade in music depends on your participation.
Student: I don't care if I get an F.

Based on our conversation last week, is this okay? Should this student have the right not to participate in class?