Which relation is a function?

A

Step-by-step explanation:

A function is that of which has only one x value. Therefore you are looking for the graph that does not have multiple x values. Doing a vertical line test to see whether there is more than one point on a line of the graph will show you that A is the only one that has one answer for each x value that is given. All the other graphs have two points for some of the x's, which makes them not a function.