A scientist wants to study the effect of vitamin C on colds. He gave 1000 mg of vitamin C per day to 100 people. What would be the best control?
A. Give the control group a pill similar to vitamin C but containing no vitamin C (a placebo)
B. Give the control group 2000 mg of vitamin C per day
C. Give the control group orange juice every day
OD. Give the control group nothing.
O E. Give the control group 1000 mg of another brand of vitamin C per daY