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". 

Ex Input:
[header] How to buy a wood burning stove [title] Consider your heating needs by evaluating the size of your home. [step] You will need to determine the heat load necessary to maintain the square footage of the area you want heated. Heat load is measured in btus, or british thermal units. <sep> (A) Inquire about btus and thermal units using online resources. [substeps] Btus heat packs can be found at home improvement stores, department stores, and some gas stations. (B) To determine how much heat you need, pay attention to the dimensions of each room you intend to fire in. [substeps] The larger the square footage, the larger your fire seats will need to be. (C) You will need 25 to 30 btus per square foot. [substeps] Measure each room to be heated with measuring tape. (D) Btus are rated from 2000-1000. Btus can be changed or altered depending on the size of your home.

Ex Output:
C


Ex Input:
[header] How to use docusign on pc or mac [title] Open the docusign email. [step] Use this method if someone sent you an email containing a docusign document that must be signed. [title] Click review document. <sep> (A) [step] This will take you to the archived documents section. [title] Click the document you wish to delete. (B) [step] When the email is finally redirected to your email inbox, you'll see a checkmark beside the discussion item (e.g.: " news sources "). [title] Click the checkmark next to your reference item item at the top of the current page. (C) [step] Your document will have been reviewed by the ftc. Ask for experience diagnosing ftml errors. (D) [step] It's the yellow button in the email. [substeps] If the sender requires you to verify your identity, follow the prompts to do so.

Ex Output:
D


Ex Input:
[header] How to save files to a usb flash drive [title] Insert the flash drive into a usb port on your computer. [step] Make sure that you don't force the drive into the port; it only goes in one way. [title] Ensure that the flash drive appears on your computer. <sep> (A) [step] If it doesn't, then you have a 5.7 mb drive. [title] Backup important files if you want to place them into storage. (B) [step] Usb flash drives are often referred to as " hd, " as these are the kind of drives that connect objects to the usb ports on almost any computer. [title] Verify that the flash drive has an idle cycle. (C) [step] Most people don't, but you will figure that out, because 3d drives are hard for almost any computer. [substeps] If you're really new, look for the " no drive " label on the drive's backing or stamped firmly on the drive. (D) [step] You'll usually receive a notification that the flash drive has been detected. If these notifications are turned off, you can check to see if it is connected.

Ex Output:

D