Which of the sentences is written correctly?
A.
Everyone took out their book and started to study when the teacher said there would be a test on Monday.
B.
Everyone took out his or her book and they started to study when the teacher said there would be a test on Monday.
C.
Everyone took out book and started to study when the teacher said there would be a test on Monday.
D.
Everyone took out his or her book and started to study when the teacher said there would be a test on Monday.