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 buy penny stocks without a broker [title] Be aware of the benefits of purchasing penny stocks. [step] Because penny shares can be purchased so cheaply, they represent an opportunity for enormous gains through high-volume purchases. [title] Be aware of the downside, too. <sep> (A) [step] Penny stocks are not very liquid, meaning there may not be much demand for them, and as a stockholder, you could have trouble finding a buyer, should you want to sell your shares. In addition, the issuers of cheap stock may suffer from a weak market position and a fragile financial profile, making them risky investments. (B) [step] The penny company's corporate board (rtc) typically has very little reasonable interest in the penny stocks, and some people expect to earn between 40 and 65 percent. It can be all or most of these savings, and some people worry about them not being valued enough for business purposes. (C) [step] Penny stocks are either volatile, gaining the first recession, or being sold to a higher yield. To understand what risks penny stocks can pose for those returns, you should look at the non-penny banks. (D) [step] Penny stocks offer many advantages for the public when buying a stock. These advantages can include substantial advancements in commission rates, larger returns, and cash reduction.

Ex Output:
A


Ex Input:
[header] How to buy a last minute cheap flight [title] Check airline newsletters, websites that specialize in last minute air travel and the travel section of your local newspaper to find last minute deals on flights. [step] Sometimes you can save money by booking flights late because airlines that have not filled their planes will offer discount fares. [title] Compare airfares from different airlines, websites and travel agencies. <sep> (A) [step] Look at every airline's website so that you can compare and contrast prices. [title] Opt for free flights as before, otherwise follow the full booking program and you'll not miss your flight in a long time. (B) [step] Try booking flights from big-ticket airlines such as kiwi airlines and delta. [title] Compare prices from travel agencies that are offering cheaper flights. (C) [step] Purchasing flights directly from the airline is not always the cheapest deal, so check out a few different travel websites and travel agencies to compare prices. [title] Search for flights during undesirable days and times. (D) [step] Compare each airline's prices with the prices you are interested in. You might be able to find a cheaper flight for free.

Ex Output:
C


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