Which is the sentence fragment?

Mrs. Finch, my calculus teacher, is crazy. She gives us twenty problems to solve each night. In class, she calls on students. Even if they haven’t raised their hands. Worst of all, she makes you come to the board to solve the problems in front of the entire class!
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A. In class, she calls on students.

B. She gives us twenty problems to solve each night.

C. Mrs. Finch, my calculus teacher, is crazy.

D. Even if they haven’t raised their hands.