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 maintain your walking regimen [title] Start slow. [step] If you've previously lived a relatively sedentary lifestyle and didn't exercise much, you need to start at a lower level than someone who has been exercising consistently throughout their life. [substeps] Be realistic about your starting goals. <sep> (A) Build up the amount of rest you get per day to this level. Aim to exercise 5-8 hours a day for the first 4 months. (B) Just getting up and walking out the front door may be all you can do for a few days. Get used to the habit and go a little further each day. (C) You want to feel confident as you develop power and endurance throughout your life, and lose the momentum you may feel as you begin to move faster. You want to be able to focus on setting a steady pace and extending a long stride without stopping. (D) If you continue with early exercise at a normal age and plan to work your way up to more intense exercise around age 12, for example, you may not be as active as you once were. You still want to make sure that you stick to a healthy, consistent exercise regimen regardless of your age.
Output:
B