Which of the following would *most* strengthen the argument that a new employee wellness program directly caused improved employee morale, after an initial survey showed higher scores?

The correct answer to the question "Which of the following would *most* strengthen the argument that a new employee wellness program directly caused improved employee morale, after an initial survey showed higher scores?" is Option C: A control group of employees who did not participate in the wellness program showed no change in morale scores..

The other options — A) A similar company without a wellness program also reported improvements in employee morale during the same period., B) Employees reported in follow-up interviews that the wellness program was their favorite new company initiative., D) The company's overall profits increased significantly in the quarter following the program's implementation. — are incorrect for this GMAT Exam Prep question. As explained above: Using a control group helps isolate the impact of the wellness program, providing stronger evidence that the program, rather than other factors, was responsible for the morale improvement.