There is one sentence in the choices below that does NOT have a grammar error by shifting mood or verb voice incorrectly. Which sentence is it? (Illuminate) (1 point)
A. Read the first two chapters, and then you should meet with the study group.
B. Two children left the classroom without permission, but they were found immediately.
C. When the operator turned on the machine, a squeaking sound was heard.
D. All members should register for the trip by noon Friday, and don't be late.