Question

why is your choice above a function?
each input value (x) corresponds with no more than one output value (y).
the relation fails the vertical line test.
there is at least one vertical line that contains more than one ordered pair from the relation.
there is at least one x - value that has more than one y - value paired with it.

Explanation:

A function is defined such that every input (x-value) has exactly one output (y-value). This matches the first option. The other options describe characteristics of relations that are NOT functions: failing the vertical line test, having a vertical line with multiple ordered pairs, and an x-value with multiple y-values all indicate non-functions.

Answer:

Each input value (x) corresponds with no more than one output value (y).