determine the graph that represents a function.

Explanation:

Step1: Recall vertical - line test

A graph represents a function if any vertical line intersects the graph at most once.

Step2: Analyze first graph

The first graph is a circle. A vertical line can intersect a circle at two points, so it is not a function.

Step3: Analyze second graph

The second graph is a parabola opening to the right. A vertical line can intersect it at two points, so it is not a function.

Step4: Analyze third graph

The third graph is a straight - line. Any vertical line will intersect the straight - line at exactly one point. So it is a function.

Answer:

The third graph represents a function.