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 introduce a pleco to a goldfish tank [title] Ask how large the pleco will grow to be. [step] Although most pet stores will sell plecos that are only a few inches in length, you should know that they can grow quite large. Fully grown plecos can reach up to two feet in length. <sep> (A) [title] Check your tank's surface before you place the pleco into the tank. [step] Make sure that your aquarium is opaque or has a drop-down tray so that your pleco is not exposed to water. (B) This can have a negative impact on their lifespan. [title] Choose a tank with large walls and no air holes. (C) [title] Make sure you cover more than twice the tank. [step] If you find that your pleco grows too much, cover the entire tank with a blanket. (D) The exact size of the pleco will vary depending on the species. Ask someone at the pet store how large the pleco will get before making a purchase.

Ex Output:
D


Ex Input:
We see a man teaching others to sharpen a knife in a butcher shop. The man wets the sharpening stone. Two men in the back laugh at something. the instructor <sep> (A) shows us a basket of pennies. (B) checks the knives and uses the sharpened knife to sharpen a one. (C) uses a sharpening rod for the knife. (D) puts a paper in the sink.

Ex Output:
C


Ex Input:
[header] How to make a hot oil treatment for hair [title] Buy coconut oil. [step] It is available in the baking section of many grocery stores since it has been found to be a healthy alternative to vegetable oils. It is also common at specialty and import grocery stores, and at some beauty supply stores. <sep> (A) It is safe for hair, too, as some commercial coconut oil has astringents in it, making it very safe to use. [title] Stir the coconut oil in a bowl. (B) [substeps] For maximum benefits, consider using 1/2 of coconut oil per 36 hours of cooking time. Soak your hair with coconut oil as needed each day to stimulate hair growth. (C) [substeps] Coconut oil has a mild, yet strong, odor. Do not use coconut oil if you plan to use it in combination with other oils. (D) [substeps] Coconut oil is usually sold in a jar. It is solid at room temperature but will turn to a liquid in the palm of your hand.

Ex Output:

D