The correct answer is:
Table A represents a function but table B does not represent a function.
Explanation:
A function is defined as a set of ordered pairs in which each element of the domain (x) is mapped to one element of the range (y). This means that every x has no more than 1 y associated with it.
In Table A, each x is mapped to only 1 y. 3 is mapped to 1; 2 is mapped to 0; and 1 is mapped to 0. While 0 is reused for the y-coordinate, each x-coordinate remains mapped to only 1 y, so Table A is a function.
In Table B, there is an x that is mapped to 2 different y-coordinates. 3 is mapped to -2; but 5 is mapped to both 1 and 2. Since an x is mapped to more than 1 y, Table B does not represent a function.