Determine which relation is a function.

Option D is a function

Step-by-step explanation:

To check whether relation is a function we use vertical line test.

Draw vertical lines on the graph, when any vertical line crosses more than two points then the relation is not a function.

Option A, vertical line crosses two points at x=-1. It is not a function

Option B, vertical line crosses two points at x=-2 and x=2. It is not a function

Option C, vertical line crosses two points at x=0. It is not a function

Option A, vertical line does not cross any  two points. It is a function