Answer:
D
Explanation:
We can use the "vertical line test" to determine whether a given graph represents a function or not.
If your vertical line intersects the graph in more than one place, the graph does NOT represent a function. Thus, D does not represent a function, as a line drawn vertically thru this graph intersects the graph multiple times.
Graph A: Note that if you draw a vertical line thru x = -2, your line will intersect the BLACK dot (-1 3/4, 0) and the EMPTY circle (-1 3/4, 3 1/4). This is OK; this graph represents a function.