Which of the following functions is the inverse of the function {(1,2),(3,4),(6,8)}?

a. {(6,8),(3,4),(1,2)}
b. {(2,1),(4,3),(6,8)}
c. {(2,1),(4,3),(8,6)}
d. {(2,1),(3,4),(8,6)}

swap values, and you need

(2,?),(4,?),(8,?)

where the ?'s must match the 1st numbers