Which of the following represents a function?
A.
x -11 -7 -1 -1
y 18 16 18 17

B.
x -11 -7 -1 -7
y 18 16 18 17

C.
x -11 -7 -11 5
y 18 18 24 17


D.
x -11 -7 -1 5
y 18 16 24 18