Stephen researched the topic of solar-powered light for his science project. He exposed 10 new solar lights to five hours of sunlight. He recorded the number of minutes each light. continued to shine after dark in the list below.

63, 67, 73, 75, 80, 91, 63, 72, 79, 87

Which of these numbers is the mean of the number of minutes in Stephen's list?

A. 28

B. 63

C. 74

D. 75