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".
Q: [header] How to use the apple watch breathe app [title] Open the breathe app. [step] The icon is green and contains a white curved arrow. [title] Turn the digital crown to set the length of your exercise. <sep> (A) [step] If you are within a set time range, tap the hour icon (an arrow symbolizes the hour and time sequence in milliseconds). [title] Tap the " breathe screen " app. (B) [step] When used properly, the app's duration is equidistant from the current duration of the exercise. The length of the exercise varies by model, but the maximum length for a human exercise week (or for the entire week) is one and six hours. (C) [step] The screen will also say " set time ". ( alternatively, use the latitude and longitude values in the run screen. (D) [step] You can choose from 1 to 5 minutes. [title] Move to a location where you can remain still and uninterrupted.
A:
D