Benefit of exercise is

Concept: Regular physical exercise does not act on the body in an isolated way — it triggers simultaneous, coordinated adaptations across several body systems at once: the digestive system (energy and appetite regulation), the musculoskeletal system (strength, coordination, and agility), and the cardiovascular system (heart and blood-vessel efficiency).

Application: In this question, each listed effect belongs to a genuine, well-documented physiological response to exercise. Increased physical activity raises energy expenditure, which stimulates the appetite-regulating centres and increases hunger. Repeated movement training improves neuromuscular coordination and joint mobility, which is what produces greater agility. Sustained physical activity strengthens the heart muscle and improves vascular tone, which increases blood circulation. None of these three effects contradicts another — they occur together as part of the same overall adaptation.

Cross-check: Since each of the three listed effects (appetite, agility, circulation) is independently verified as a real benefit of exercise, no single one of them alone is the "benefit of exercise" — the complete and correct description covers all three together.

Result: Hence, the correct answer is "All of the above."