Given the relation R = {(3, 7), (2, y), (x, 5), (1, 6), (4, 8)). Which of the following values of x
and y will make the relation R a function?
A. x = 1, y = 3
B. x = 5, y = 5
C.x = 4, y = 9
D. x = 3, y = 4