SOLUTION
Given the question in the image, the following are the solution steps to answer the question.
STEP 1: Define vertical line test
If a vertical line intersects a curve on an xy-plane more than once then for one value of x the curve has more than one value of y, and so, the curve does not represent a function. If all vertical lines intersect a curve at most once then the curve represents a function.
STEP 2: Perform the vertical line test on the graph in 12
The graph did not pass the vertical line test since there are vertical lines that pass through more than one point on the graph.
Hence, the graph does not represent a function since the line crosses the graph twice.