Does the graph represent a function, why or why not ?

Answer:
D. Yes, because it passes the vertical line test.
Step-by-step explanation:
First let's see what a horizontal line test and vertical line test.
Horizontal Line Test: A test use to determine if a function is one-to-one. If a horizontal line intersects a function's graph more than once, then the function is not one-to-one.
Vertical line test: The function y = f(x) is a function if it passes the vertical line test. if we draw a vertical line it cuts the graph only one point on the graph, then it is a function or else it is not a function.
Here we want to find the given graph represents the function or not.
We have to use the vertical line test.
If we draw a vertical line, the line cuts only one point, the line not passing through more than one point.
Therefore, the given graph represents a function.
Answer: D. Yes, because it passes the vertical line test.
Thank you.