Which of the following is a question regarding a client's exercise history?

The question "Are you currently exercising?" directly pertains to a client's exercise history because it seeks to understand the individual's current level of physical activity and their experience with exercise. This information is crucial for evaluating a client's fitness background and developing a tailored exercise program that suits their current capabilities and goals.

The other options, while they may provide context about the client, do not specifically inquire about their exercise history. Asking about shoe size may relate to footwear needs but does not give insight into exercise habits. The occupation can influence a person's lifestyle and available time for exercise, yet it does not directly address their exercise patterns. Inquiring about watching sports on TV is unrelated to a client's active participation in physical activities and does not provide information on their exercise experience. This makes the correct choice clear, as it directly assesses the client's ongoing engagement with physical activity.