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.

Darren 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. Darren had to decide when the filter was too clogged and needed to be replaced. So, during his inspection, Darren checked the filter by measuring how quickly water moved through it.
Figure: an engineer at a water treatment plant.
Which of the following could Darren's test show?
A. the amount of bacteria in the water before it was filtered
B. whether an inexpensive filter would become clogged more often
C. whether the filter was clogged
Identify the correct option from the choices provided and respond with the letter of the correct option.

C