If the Function Is One-To-One, Find Its Inverse

Multiple Choice

If the function is one-to-one, find its inverse. If not, write "not one-to-one."
-{(-2, 4) , (2, -4) , (8, -2) , (-8, 2) }

A) not one-to-one
B) {(4, -2) , (-4, 2) , (-2, -8) , (2, 8) }
C) {(4, -2) , (-4, 2) , (8, -2) , (2, -8) }
D) {(4, -2) , (-4, 2) , (-2, 8) , (2, -8) }