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 Input: [header] How to polish rocks [title] Choose the right rock. [step] You can polish any stone you wish, but there are certain characteristics of a stone that will make it easier to polish. If you want an easy stone to polish, pick a somewhat softer stone like onyx, limestone or calcite. <sep> (A) [substeps] You can polish diamond, granite or ceramic stones by cutting thin pipe holes or inserting dry mortar into one side of each hole. Look for a stone that resembles a diamond, but not necessarily a diamond. (B) Otherwise, a smoother, more pumice-like stone will be more difficult to polish. [substeps] Emeralds and equilateral manganese are both excellent mineral polishes. (C) Stones that are very hard will take a much longer time to polish. However, though hard rocks take a long time to sand, they yield more shine than softer rocks. (D) Softer rocks will actually work more well, and might look better to polish very old stones, but brighter stones tend to chip quicker. [substeps] Rubies, sapphires, and emerald are good options.
Example Output: C

Example Input: [header] How to install debian [title] Back up any important files on your computer. [step] Installing debian on your machine will clear your entire hard drive and reformat it, erasing all data in the process. Store your important information on a removable drive before beginning the installation. <sep> (A) [title] Navigate your web browser to the debian website. [step] Debian is distributed through www.debian. (B) [substeps] If you don't own one, ask a sales associate at your bank to store your files in your. Otherwise, you can install them on your own hard drive. (C) [title] If debian has dependency on your operating system in the previous step. [step] Some debian programs allow for debian to be connected to external storage like the usb connector, vertical port or the simplest root driver. (D) [substeps] Make sure to click the " save/install " button right on the back of the removable drive. [title] Locate and modify the " reason for installing debian " website.
Example Output: A

Example Input: [header] How to choose to be happy [title] Recognize your right to be happy. [step] Before you can begin to be happy in general, you have to believe that it's okay for you to be happy. You have to accept that you may not be perfect and may have made mistakes, but you still have the right to smile, laugh, and feel joy and excitement. <sep> (A) [substeps] It's important to notice and accept that you are imperfect. In fact, accept yourself the same way you are-remove a blank part of yourself that you didn't know you had. (B) [substeps] Knowing that you do have the right to feel happiness may help you maintain a positive attitude towards life and moving forward. Be mindful that engaging in any kind of work or hobby will only hamper you in doing so. (C) If you can't be happy, that's okay too. Recognizing how it's okay to be happy doesn't mean to give up your happiness and allowing the world to give you what it needs. (D) [substeps] Try looking in the mirror and telling yourself, " i deserve to be happy, and that's what i'm going to do ". In your journal each day, write an affirmation of your right to be happy.
Example Output:
D