Which of the following is a function?

A. (-2,3), (0,3), (1,6), (1,-6)

B. (-2,4), (0,3), (1,6), (-1,2)

C. (1,3), (2,4), (1,5), (2,3)

D. (1,-1), (2,-2), (1,-3), (4,-4)

B. (-2,4), (0,3), (1,6), (-1,2)

Step-by-step explanation:

The list of first numbers for a function is a list of unique numbers.

A: 1 is repeated

B: the 4 pairs have 4 different first numbers: {-2, - 1, 0, 1}

C: 1 and 2 are repeated

D: 1 is repeated