HURRY!

Given the function ƒ = {(1 , 2), (2 , 3), (3 , 4)} write the set of ordered pairs representing ƒ -1.
Select one:
a. {(1, 2), (3, 2), (4, 3)}
b. {(2,1), (3, 2), (4, 3)}
c. {(2, 1), (2, 3), (3, 4)}