We were rivals in class, good students who read Vonnegut and announced, to our piano teachers' pleasure and our classmates' befuddlement, that we preferred classical music to Duran Duran. We should have been friends. For some reason, C chose to go in the other direction.
Meet with your child to find out his/her version of the situation. Try not to accuse your child. Instead, ask the child what happened that day and what parts of the story that you heard were true.
There are a few places no one should enter without an advocate--a courtroom, a hospital and school. But only a parent can properly advocate for their child in school where a bully is concerned.