Which is the best correction for the inappropriate shift in pronoun in this passage?

Mr. Bryson always warns his third class to be careful with the saws because they are made up of students who often don't listen.

A. Change "they are" to "it is."

B. Change "his" to "their."

C. Change "they" to "we."

D. Change "his" to "its."

A. is correct.​