Does this graph show a function? explain how you know

Answer:
yes it is a function D
Step-by-step explanation:
When you draw a vertical line through any part of the parabola, you will see that it will only intersect with one point.
B is not the answer because it would not matter if there are no y values that have more than one x value becuase the statement that matters is...
each x value should have 1 and ONLY one output (or y-value)