Question

why is your choice above not a function?
there is not a vertical line that would contain more than one ordered pair from the relation.
the relation passes the vertical line test.
each input value (x) corresponds with exactly one output value (y).
there is at least one x - value that has more than one y - value paired with it.

Explanation:

A relation is a function if every input (x-value) has exactly one output (y-value), which is verified by the vertical line test: a vertical line drawn anywhere on the graph should not intersect the relation more than once. The selected graph has vertical lines that pass through multiple points, meaning some x-values are paired with more than one y-value, so it fails the vertical line test and is not a function.

Answer:

There is at least one x-value that has more than one y-value paired with it.