A prospective cohort follows 600 students: 200 exposed at game nights and 400 unexposed. After follow-up, 50 exposed students developed illness and 20 unexposed developed illness. What is the relative risk (RR) of illness for exposed versus unexposed?

• A. 0.2
• B. 3.5
• C. 5.0
• D. 1.25

Answer: (C)