Which set of ordered pairs dose not represent a function?

C

Step-by-step explanation:

For a relation to be a function, each x-value can only have one corresponding y-value and would, in turn, pass the vertical line test, a way to determine in a graph is a function. Since set C features the points (5, 4) and (5,7), an x-value with two corresponding y-values, this set of ordered pairs does not represent a function.