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

If the function is one-to-one, find its inverse. If not, write "not one-to-one."
-{(4, 5) , (7, 5) , (1, 4) }

A) not one-to-one
B) {(4, 5) , (5, 7) , (4, 1) }
C) {(5, 4) , (1, 7) , (4, 5) }
D) {(5, 4) , (5, 7) , (4, 1) }