Question

If a scientist wants to design an experiment to measure the effect of vitamin C on colds, which of the following would be an appropriate placebo?
a. half the recommended daily amount of vitamin C
b. a sugar pill that does not contain vitamin C
c. the recommended daily amount of vitamin D
d. the recommended daily amount of vitamin C

Answer 1

Answer: b.  A sugar pill that does not contain Vitamin C

Explanation:  

It has to be a sugar pill because a placebo (or dummy pill) is an inert (inactive) substance, typically a tablet, capsule or other dose form that does not contain an active drug ingredient.