Researchers testing new drugs usually give the drug to one group of people and give placebos, "sugar pills," to another group. The group receiving the placebo:
A) constitutes the experimental group.
B) is a backup in case some of the people getting the drug drop out of the test.
C) is needed so that the test will be repeated enough times.
D) is the control group.

Researchers testing the new drugs usually give the drug to one group of people and give placebos, " sugar pills" to another group.The group receiving the placebo is D) the control group

Explanation:

Placebos are often used in clinical researches as well as trials as an inactive control because it will help the researchers in the evaluation of the overall effect of the experimental drug treatment under the research. In addition the scientists/ researchers would also want to know which patients have receive active or placebo treatments. Placebos will also help the researchers during their research to help them to understand what effect that prescribed drug or medicine might have on a particular condition. It will help the researchers to evaluate the comparisons between the effects of drug and the placebo on the people who have taken part in the experiment/study. Placebos are most commonly used in the blinded trials where the patients don't know whether they are getting the real treatment or placebo treatment. The purpose of the placebo group is to be held accounted for the placebo effect, the effects which is from experiment/ treatment that does not depend on the treatment itself. The placebo effect is effect/impact on a person who has received a placebo. The impact is often positive & placebo is a substance eg.sugar pill which is given to an individual group instead of an actual drug/medication. The placebo are made to exactly look like a real drug/ medicine but they are made up of inactive substance such as starch or sugar. Placebos now a days are used only in studies/research.