NASM uses the SMART goal framework-Specific, Measurable, Attainable, Realistic, Timely-to help clients set effective goals. The statement "I want to be in better shape in 1 month" is vague because "better shape" is not defined or measurable.
By contrast, the other goals: losing 8 pounds in 1 month (Option A), running a 5K in 1 month (Option B), and going to the gym three times a week for 1 month (Option C) are more specific and measurable. The trainer should clarify vague goals by asking probing questions to define what "better shape" means to the client (e.g., improved strength, endurance, weight loss). Therefore, the goal requiring clarification is Option D.