Final answer:
A waist circumference exceeding 40 inches would require a male client to seek medical clearance before starting an exercise program due to the increased cardiovascular disease risk associated with central obesity.
Step-by-step explanation:
The measurement that would require a male client to obtain medical clearance before participating in an exercise program due to cardiovascular disease risk is A. Waist circumference exceeding 40 inches. A high waist circumference, specifically above 40 inches, can be indicative of central obesity, which is associated with a higher risk of cardiovascular disease. This measure can be particularly concerning because observational studies have shown that individuals with "apple-shaped" bodies, who carry more weight around the waist, have greater risks for chronic disease than those with "pear-shaped" bodies, who carry more weight around the hips.
In contrast, B. Resting heart rate of 65 beats per minute is within the normal range, C. Body mass index (BMI) of 25 is considered the threshold for overweight and not necessarily an immediate risk for healthy individuals without other symptoms, and D. Blood pressure of 120/80 mmHg is considered a normal reading.