In a Study Designed to Test the Effects of a New

In a study designed to test the effects of a new drug developed to treat Alzheimer's disease,half the patients were given the actual drug while the other half of the patients were given a placebo (sugar pill) .In this study,the experimental group is

A) the patients who show evidence of an improvement in their memory.
B) the group who received the actual drug.
C) the group who received the placebo.
D) the patients who were not included in the study.