Answer:
The ordered pairs of A and C are not functions
Explanation:
To determine if the ordered pairs are a function you look at the x values to see if they repeat. You don't want one input(x values) to lead to two outputs(y values). This would mean that you are never sure which output you will get.
In the answer A the x value "2" repeats, in the answer C the x value "1" repeats thus not making them functions.