Determine which of the following sets of ordered pairs represents a function. A. {(12,−9), (12,4), (12,3), (12,−1)}

B. {(4,−9), (10,12), (4,3), (10,−1)}

C. {(−16,−9), (10,4), (7,3), (−16,−1)}

D. {(−16,−9), (10,−9), (4,−9), (7,−9)}