which of the following sentences is in passive voice

C)"A whole case of beer gets drunk every Saturday night"
is passiv.

The passive voice is real handy when it comes to ducking responsibility. When someone starts off "It has been decided. . . .", you can be sure there is no individual who wants to accept the blame.

In C), in other words, who drank all the damn beer?

Also, you should use spaces after punctuation like parentheses.