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 study the phenomenon of light as a nonequilbirum state of matter [title] Understand how thermodynamic systems are categorized. [step] Thermodynamic systems in nature are divided into two types. One is systems that are at equilibrium state with the environment and the other is systems that are in a state of nonequilibrium with the surroundings. <sep> (A) On earth, nature has a preference for systems that are at an equilibrium state with the surrounding. This is so due to the principle of minimum energy that every object in the universe aspires to have. (B) For example, gas rising in temperature throughout the day can be divided into microorganisms in the environment. [substeps] For example, gas rising in temperature in the atmosphere can be divided into molecules in the environment. (C) [substeps] Equilibrium is fundamental in thermodynamics. Other systems include stars, planets, and oceans. (D) [title] Learn about the term " rock hydrodynamics ". [step] Rock hydrodynamics refers to the transfer of water to the earth's surface.

Ex Output:
A


Ex Input:
A black object appears and the woman is now placing it onto a long pole, she's back on the ladder and she's using the black object to help her hold up the border wall paper as she applies it all along the wall. when the woman <sep> (A) finishes the wall paper is covered by a blue curtain and she begins to pull the white rod back and forth as she continues to use the soldering iron to create the wall paper. (B) has drawn a border on the wall, she stretches up to get a better hold, three inches above the floor leaving the wall covered in white paper. (C) is done plastering, she takes the phone back and the actual wall paper is now in place and it seems to be the perfect size, exact size and it has sparkles, three big black holes in it and it has the laminate look to make it look very clean. (D) is done the camera pans to show the finished job and the outro appears that includes the website, company name, price and phone number.

Ex Output:
D


Ex Input:
He has several rubik's cubes in a row. He is timing himself as he attempts to solve the cube. he <sep> (A) shakes his head as a then solves the cube in several quick seconds. (B) moves quickly, solving them in short time. (C) uses the timer to give him more minutes. (D) finishes and sets the watches timer.

Ex Output:

B


