Which graph represents a function?
A. A coordinate plane shows 4 points with the following coordinates: (negative 4, 4), (negative 2, 1), (2, 1), and (2, negative 4).
B. A coordinate plane shows 4 points with the following coordinates: (negative 3, 3), (negative 1, 1), (negative 1, negative 2), and (1, 3).
C. A coordinate plane shows 3 points with the following coordinates: (negative 3, 3), (negative 2, negative 2), and (negative 1, 1).
D. A coordinate plane shows 4 points with the following coordinates: (negative 2, negative 2), (negative 2, negative 3), (3, 4), and (3, negative 4).