the oposite of a number is located on the oposite side of the 0 on the number line
the oposite of a number is the negative of a number, if the number is already negative, double negative cancels to make positive
so
oposite of -12 is +12
A. false, they are on oposite sides
B. false, it is 12, not -1/12 (just fyi, later you will learn that -1/12 is the reciprocal of -12 but that doesn't matter right now)
C. correct, -12 is 12 units behind 0, 12 is 12 units after 12
D. what, are they joking, wrong
C is the right answer