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 exercise to prevent blood clots [title] Get up and move around. [step] Whether you're traveling by train, plane, or automobile, long-distance travel involves a lot of sitting. When you sit, you decrease circulation in your legs-especially if you sit with your legs crossed or with one foot under you. <sep> (A) If you are on a train or coach, the seat underneath you always feels flat, as if you are sitting. While there are good ways to stretch out your legs, there is not a lot a group of people can do. (B) This will help promote blood circulation to your feet. It will also keep you from rubbing your legs in an annoying manner-you can't promote blood flow when you're sitting on one leg. (C) [substeps] You can exercise while you drive or driving, although getting up and down on the exercise train can significantly improve circulation. You can also listen to music while you exercise, which will also help to prevent blood clots. (D) [substeps] If you're on a plane, try to get an aisle seat so you can get up and move around more easily. Ideally, you want to get up and stretch your legs or walk up and down the aisle once every hour or so.

Ex Output:
D

Ex Input:
[header] How to post to a facebook group on pc or mac [title] Go to https: // www.facebook.com in a web browser. [step] You can use any web browser, such as chrome or safari, to access facebook. If you're not already signed in, sign in now. <sep> (A) [title] Click on the downward-facing arrow in the top right corner of the screen. [step] It's at the top-right corner of the screen. (B) [title] Click your profile picture at the top-right corner of the page. [step] You will see your profile picture in the upper-right corner of the page. (C) [title] Click a group to open the group's menu. [step] Click the group on the right sidebar, or the group's upper menu of options. (D) [substeps] You must already be a member of a group to post to it on your computer. See join groups on facebook to learn how to join a group.

Ex Output:
D

Ex Input:
[header] How to start an ice cream truck business [title] Outline the costs of the truck. [step] A reliable van or truck large enough for freezers to keep the ice cream cold can cost between $10 , 000-$20 , 000. This will be the biggest upfront cost for the business. <sep> (A) Include any costs in terms of the layout, the seat, the fuel market and gas prices. Also include any equipment that might be needed and the technical materials for the truck. (B) The same is true if the whole truck is too small. [title] Sketch a sketch of business (prices, parking, etc. (C) [substeps] You can try to get the van or truck used to save some money on it, though you should make sure the van or truck will run reliably. You can also look for a van that already has freezers in it to save on outfitting costs. (D) Think about selling in bulk to make in bulk all the benefits available for you. [substeps] That costs include parking, fuel, ice cream, and more.

Ex Output:
C