Dr Stone Designs a Study to Test the Effectiveness of a New

Dr. Stone designs a study to test the effectiveness of a new treatment for anxiety disorders. After making sure that her participants are roughly similar on important demographic variables, people are randomly assigned to receive either the new therapy or another therapy technique that has already been proven to be effective. Which of the following statements best describes Dr. Stone's study?

A) Her study does not use randomized clinical trials, but it does have a placebo control group.
B) Her study does not use randomized clinical trials, and it does not have a placebo control group.
C) Her study uses randomized clinical trials with a placebo control group.
D) Her study uses randomized clinical trials, but does not have a placebo control group.