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.

Valentina was designing small aircraft called drones to pick up items from warehouse shelves. She knew that the drones' propeller blades would get damaged if they bumped into anything while flying through the warehouse. So, Valentina wanted to add blade guards to protect the propeller blades. The guards had to be sturdy so they would not break in a crash. But she thought that if the guards weighed too much, the drones would not fly well.
So, Valentina put guards made of lightweight metal on one drone. Then she observed how well the drone flew with the guards.
Figure: a drone without blade guards.
Which of the following could Valentina's test show?
A. how much the drone weighed with the blade guards
B. if the blade guards would break in a crash
C. if adding the blade guards made the drone fly poorly
Answer with the option's letter from the given choices directly.

C