A nurse is working in a clinical research trial that has a control group and an experimental group but does not know which group is receiving the active drug. Which statement best identifies the research design?

A. Placebo group: A placebo group refers to participants receiving an inactive substance or placebo, not the research design itself. B. Experimental drug: The term "experimental drug" refers to the drug being tested, not the design of the study. C. Control group: The control group receives the placebo or standard treatment for comparison, but this term does not describe the study design. D. Double-blind: A double-blind study is one in which neither the participants nor the researchers know who is receiving the active drug or placebo. This is the correct term for the described scenario.