To determine which of the graphs is a function, we can apply the vertical line test. This test states that if any vertical line intersects a graph at more than one point, then the graph does not represent a function.

Let's analyze each graph:

• Graph A: A vertical line can intersect the graph at multiple points (e.g., the loop on the left side), so it is not a function.
• Graph B: A vertical line can intersect the graph at multiple points (e.g., at the left side), so it is not a function.
• Graph C: A vertical line intersects the graph at only one point in any vertical line you draw. This means that it is a function.
• Graph D: A vertical line can intersect the graph at multiple points (e.g., the top and bottom of the circle), so it is not a function.

Answer: C) Graph C

Would you like a more detailed explanation, or do you have any other questions?

Here are five relative questions for you:

1. What defines a function in mathematical terms?
2. How does the vertical line test help in identifying a function?
3. What are some examples of functions that fail the vertical line test?
4. Can a graph that passes the vertical line test ever represent a non-function?
5. How do piecewise functions behave under the vertical line test?

Tip: Understanding the vertical line test is crucial for quickly identifying functions from their graphs.