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 use psychology to close more sales [title] Give something for free. [step] The principle of reciprocation is a psychological phenomenon described by dr. robert cialdini, an expert in persuasion. According to this theory, it is part of human nature to feel obligated to repay debts of all kinds, big and small. <sep> (A) To begin this process, ask yourself if you really are willing to sell something for free. If you are willing to throw in the money, then you are probably willing to take credit. (B) You can't force anything on someone else. [substeps] If you " feel " obligation to a friend or loved one, give them something to ask you " if i use this method, what will happen? " [title] Assemble your argument. (C) If someone receives something free, they will feel a psychological urge to purchase a product to pay you back for your kindness. [substeps] Offer a free trial period, a sample, or even a pleasant experience. (D) To do this you must pay for or at least accept the full offer. After that you must devise a plan of compensation.

Ex Output:
C


Ex Input:
A man wearing grey shorts kneels down on a carpeted floor and begins stretching. The man moves his right leg under his hip and in front of his left knee. the man <sep> (A) continues exercising his left leg. (B) is then sitting while he's exercising and putting a harness. (C) then begins looking comfortable about doing this and stretches. (D) begins to rock back and forth in a slow movement as he stretches.

Ex Output:
D


Ex Input:
[header] How to paint watermelon nails [title] Remove any old nail polish. [step] Soak a cotton ball or pad with nail polish remover. Rub the soaked cotton ball over the old nail polish gently to remove the polish. <sep> (A) [substeps] Rinse away the polish from the peel and gently scrub away the residue, to avoid further staining the polish. You do not have to cover the peel in nail polish remover. (B) Don't wipe the wet cotton onto the watermelon, but rather gently rub it over the nail until the paint is lost. [substeps] Washing the cotton ball between uses will get rid of any old paint. (C) You can also wear gloves to avoid damaging your fingers. [substeps] The rubbing motion will help the polish to adhere to the nails. (D) [title] Paint your entire nail a light pink or red, the color of watermelons. [step] After applying a clear base coat apply a thin coat of pink or red polish starting at the base of the nail and working your way up.

Ex Output:

D