Which of the following sets represents a function?
A{(3, 5), (-1, 7), (3, 9)}
B{(1, 2), (3, 2), (5, 7)}
C{(1, 2), (1, 4), (1, 6)}
A{(3, 5), (-1, 7), (3, 9)}
B{(1, 2), (3, 2), (5, 7)}
C{(1, 2), (1, 4), (1, 6)}