Context: People can use the engineering-design process to develop solutions to problems. One step in the process is testing if a potential solution meets the requirements of the design.
The passage below describes how the engineering-design process was used to test a solution to a problem. Read the passage. Then answer the question below.

Tommy was . At the plant, an expensive filter was used to remove disease-causing bacteria from the water. But over time, the filter would become clogged with bacteria. If the filter became clogged, the water would not move through quickly enough. Tommy had to decide when the filter was too clogged and needed to be replaced. So, during his inspection, Tommy checked the filter by measuring how quickly water moved through it.
Figure: an engineer at a water treatment plant.
Which of the following could Tommy's test show?
A. whether an inexpensive filter would become clogged more often
B. the amount of bacteria in the water before it was filtered
C. whether the filter was clogged
Identify the correct choice from the options below and respond with the letter of the correct option.

C