Applied Economics is the one class where the professor demands that

Applied Economics is the one class where the professor demands that each of her students completes the assignment before returning home for the holiday break.


A) where the professor demands that each of her students completes the assignment before returning home for the holiday break

B) in which the professor demands that each of her students, before returning home for the holiday break, completes the assignment

C) where the professor demands that each of her students complete the assignment before returning home for the holiday break

D) in which the professor demands that each of her students complete the assignment before returning home for the holiday break

E) in which, before returning home for the holiday break, the professor demands that each of her students complete the assignment


Can someone explain to me why it is incorrect to say "each of her students completes". From my experience, the GMAT explanations always tell you that "each" should be treated as a singular noun, however the correct answer (D) says the the phrase should read "each of her students complete". I chose (B). Any help on this would be great