Question

Which function has an inverse that is also a function?

a) {(–1, –2), (0, 4), (1, 3), (5, 14), (7, 4)}
b) {(–1, 2), (0, 4), (1, 5), (5, 4), (7, 2)}
c) {(–1, 3), (0, 4), (1, 14), (5, 6), (7, 2)}
d) {(–1, 4), (0, 4), (1, 2), (5, 3), (7, 1)}