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.

Garrett was installing solar panels on the roof of a client's house. The panels had to provide enough electricity to power the house year-round. Garrett needed to decide how many panels to install and which side of the roof to install them on. If he put the panels on the side that got the most sun, then he could use fewer panels, and the client would save money. Garrett installed sunlight sensors on both sides of the roof. Then, he measured the amount of sunlight the sensors on each side of the roof recorded over one sunny summer day.
Figure: installing solar panels on a roof.
Which of the following could Garrett's test show?
A. which side of the roof got more sun over one day
B. the amount of sunlight the roof would get throughout the year
C. how many solar panels could fit on each side of the roof
Select the correct answer from the provided options and reply with the letter associated with it.

A