Choose if each statement is True or False.

{(1, 2), (3, 6), (4, -7), (6, -10)} is a function:
{(1,1), (2, 2), (3, 3), (4,4)} is a function:
{(1, 3), (2, 5), (7, 9), (2, 12)} is a function:
{(1, 8), (2, 8), (3, 8), (4,8)} is a function: