Answer:
The question asks us to identify which of the provided graphs represents a function.
A relationship can be called a function only if one x-value corresponds to exactly one y-value.
To know if a relationship is a function from its graph, we can use something called the vertical line test. This is where you draw (or imagine) a vertical line going through the graph. If the line touches the curve exactly once, it passes the test and is a function.
In this question, for the first option, if we imagine a vertical line going through the graph, we can see that it touches the graph continuously at x = 1. Therefore, it is not a function.
Similarly, for the second and third options, the vertical lines would touch the graph twice. Therefore, they aren't functions either.
Finally, for the last option, we can see that a vertical line would touch the graph exactly once at every value of x. Therefore, it is a function.