If y − 1 = 4x, which of the following sets represents possible inputs and outputs of the function, represented as ordered pairs?
a. {(1, 4), (2, 8), (3, 12)}
b. {(4, 1), (8, 2), (12, 3)}
c. {(0, 1), (1, 5), (2, 9)}
d. {(1, 0), (5, 1), (9, 2)}