A set of pair of points satisfies the condition to be a function if one x-value does not have more than one y-value.
In Table D:
One x-value does not have more than one y-value.
Therefore, it is a function.
In Table E:
The x-value 2 has two y-values, 0 and -1.
Therefore, it is not a function.
In Table F:
One x-value does not have more than one y-value.
Therefore, it is a function.
