ANSWER
C. Yes; the graph passes the vertical line test.
Step-by-step explanation
The quickest way to determine whether a graph represents a function or not is to perform the vertical line test.
If the graph passes the vertical line test, the graph represents a function.
If we draw vertical line across the graph in the attachment, it will touch the graph at one and only one point.
Since the graph passes the vertical line test, it represents a function.