Definition: In this task, you are given a context and four options. Each option is a suggested ending for the context. You should read the context and pick the best ending for the context. Please answer with "A", "B", "C", and "D".
Input: [header] How to boost immunity with exercise [title] See your doctor. [step] Almost any person can boost immunity through exercise. However, what exercises and times are best for you may vary depending on your overall health. <sep> (A) Schedule an appointment with your doctor to see you are able to do a moderate exercise program to stimulate your immune system. This can ensure you are healthy enough for exercise, especially if you aren't currently exercising. (B) Call your doctor before starting any exercise regimen to check for specific recommendations or guidelines. Be sure to get this information before you begin any one-on-one activities so you don't put unnecessary stress on yourself. (C) Talk to your doctor about starting a exercise regime for yourself, and discuss which exercises and times fit into your schedule. [substeps] Your doctor will want to see your physical and mental health so that he/she can make sure that your body is healthier. (D) Speak to your doctor about which exercises are beneficial for you and consider ways to increase your immunity. [substeps] Periodically check your calorie profile to determine the recommended amounts.
Output:
A