Given the task definition, example input & output, solve the new input case.
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".
Example: [header] How to create a christmas tree forest [title] Consider the type of tree you want to plant. [step] There are a wide variety of christmas trees and include fir, pine, spruce, cypress, and cedar. These trees thrive in different climates and look different from one another. <sep> (A) It is important to research the tree before setting up your tree to try it out to make sure you can write the tree's growing season so that you can get the most supplies you need. If you're just interested in having a tree stand out, then make sure to check for the following : [substeps] Spruce trees. (B) [substeps] Trees green may be used in a mix of green and evergreen. Greens, such as pintos and olive oil, may be more delicate than these. (C) Where the trees grow together is up to you. [substeps] Spruce trees light up the night for hours in the morning and drown out the morning sunrise between afternoons. (D) Think about where your tree forest will be located and choose a tree that can thrive in that climate. [substeps] Balsam firs are a popular christmas tree species that grow in the northern united states and canada, in hardiness zones 3-5 or states like minnesota, north dakota, and montana.
Output: D
This is a good example. Only option D is about Christmas trees. So, it's the correct option.

New input case for you: [header] How to fast for a day [title] Clarify your purpose in fasting. [step] Ask yourself what you wish to learn from the experience, and use this purpose to set an intention for the day. You may find that you get much more out of the fast if there is a drive behind your discipline. <sep> (A) [substeps] Plan a quick meal for yourself and a place to fall behind. While fasting, you'll most likely do this for 12 hours, but if you start to feel tired you might want to make the whole experience a goal. (B) Consider whether you have any goals for spiritual or mental development, or whether you are simply trying to tap into the physical benefits. Meditate on a theme, a question, or a goal. (C) Try to reason that the less physically and mentally sore you feel, the more you can focus on the task at hand and also the healthier your days will be. [substeps] Sanitation is a necessary factor for success at fasting. (D) [substeps] Write down your reasons why you enjoy a fast, for example. Talk to friends or family members who have enjoyed a fast before, and ask if they'd appreciate you speeding up each time you take a fast.
Output:
B