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 calculate a light year [title] Define the light year. [step] A light year is a measure of distance equal to how far light travels in one earth year. Because distances across the universe are so large, astronomers use light years. <sep> (A) However, they can also be determined by dividing by a distance. [substeps] Some light years are used year-round. (B) For light year 2014, the main determiner is the sun. In the light year, the world is filled with light bulbs. (C) Without light years, discussing the distance between two stars would require the use of large, unruly numbers. [substeps] Another measure of distance you may come across when learning astronomy is the parsec. (D) [substeps] There are two kinds of light years: day and night. The two types of light years are known as night and day.

Ex Output:
C


Ex Input:
[header] How to unblock a toilet when you have no plunger [title] Cover the end of a mop with a plastic bag. [step] Pull the bag over the end of the mop. Then, tie it off or secure it in place with a rubber band. <sep> (A) You can also use a rag or a toilet cloth to help secure the bag if you don't have a mop. [substeps] Try using empty containers to provide more protection. (B) After securing the handle of the mop, throw it away. [title] Turn on the water faucet. (C) [substeps] Discard any waste that falls from the end of the mop. [title] Use the bucket or bowl to catch any urine that spills out. (D) [title] Plunge your toilet with the mop. [step] Use a forceful in and out motion like you would with a normal plunger.

Ex Output:
D


Ex Input:
[header] How to dispute credit report errors [title] Request a copy of your credit report. [step] The first step is to get a copy of your credit report. You should not contact each reporting agency separately. <sep> (A) However, you can request an update to be printed on your report. Check your credit report and look for a link that says " call credit reporting agency. (B) Instead, you should request a copy of a report from each agency by email or by telephone. Always speak in a conversational voice and wait for confirmation that you want to speak to the credit reporting agency first. (C) Nevertheless, you should call each agency to request a copy. [substeps] You can get a copy by visiting https: // www.consumer. (D) Instead, you can use one of the following methods for requesting a free annual report : [substeps] Call 1-877-322-8228. Your credit report will be delivered by u.s.

Ex Output:

D