If y - 4=2x, which of the following sets represents possible inputs and outputs of the function, represented as ordered pairs?
{(2, 1), (4, 2), (6, 3);
{(1,2), (2, 4), (3, 6)}
{(4, 0). (6, 1). (8.2);
{(0.4), (1,6). (2.8)}