Answer: B.) it is a one-to-one function
Explanation:
It's a function because it passes the vertical line test. It's also one-to-one because it passes the horizontal line test.
The vertical line test is where we try to draw a single line through more than one point on the blue curve. Such a task isn't possible in this case, and we consider the curve passing the vertical line test. The horizontal line test is nearly identical, but we're dealing with horizontal lines of course.
