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 girl presses a full lemon on a machine into a cup. The workers add sugar and water before shaking the cup. a straw <sep> (A) skims over a woman's shoulder. (B) is tilted into the cup and the girl dips a sip into the cup. (C) is added and the lemonade is placed on the counter. (D) is held across the machine.

Ex Output:
C

Ex Input:
[header] How to buy vegan wine [title] Perform an internet search for vegan wine. [step] Online vegan wine guides offer lists of wines that are suitable for both vegans and vegetarians. [title] Purchase vegan wine online. <sep> (A) [step] Several vegan wine distributors offer 100 percent animal-free wines from different countries. Many individual winemakers also have websites from which you can purchase vegan wine directly. (B) [step] Check the label on the bottle of a vegan wine or a mix of varieties to find out if it is vegan. [substeps] Check fermented bottles with a tag that states if it is from u.s. (C) [step] There are thousands of free online wine sites each with cans of vegan wine. You will get your curiosity up by comparing and subscribing to one, and choosing a wine on the list. (D) [step] Before purchasing any wine, head online and research the " offline " and " non-conventional " versions of the wine available. The online website should come up with several types of wines that are appropriate for a vegan and vegetarians palate.

Ex Output:
A