Mrs. Anderson is giving a test in her third-period class. She has decided to record the amount of time that each student takes to finish the test (in minutes) and compare that to the grade each student receives on the test (out of 100). A plot of her results is below. Which of the following does this situation represent?

A. both a relation and a function
B. a function only
C. neither a relation nor a function
D. a relation only