A group of student nurses are reviewing the process of drug development. Which statement best identifies the concept of a placebo?

A. A medication that supports physiological well-being: A placebo does not have active therapeutic effects and is used in research, not for direct physiological support. B. Medication designed to have more benefits than risks: This statement refers to a drug with a favorable benefit-risk profile, not a placebo. C. An inactive substance that is used for comparison in drug studies: This is the correct definition of a placebo. It is an inactive substance that has no therapeutic effect, used to compare against the active drug in clinical trials. D. The active ingredient in a drug preparation: This statement describes the component responsible for the therapeutic effect of a drug, not a placebo.