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 clean a plastic water tank [title] Open the outlet valve or tap. [step] The first step to cleaning your tank is to empty all of the water from it. To do so, open the outlet valve or tap at the bottom of your tank and let all of the water flow out. <sep> (A) [substeps] You may find that there's extra water in your tank that you need to empty. Read the instructions carefully to see if your water is full enough to remove. (B) You will have to remove several pieces of tank flooring to access one. For the best results, take the steps above. (C) Then, use a bucket to wipe the water down away from the water line, then gently empty the tank contents into the toilet. [substeps] You should also clean the water tank once every few months to keep it clean. (D) [substeps] Connect a hose to the open valve in order to direct the water to a location where it will not cause any localized flooding or erosion. Permanent water tanks have a washout valve that is located at the base of the tank.

Ex Output:
D

Ex Input:
[header] How to do chest exercises in yoga [title] Do the mountain pose to warm up, plus a couple of humming bee breathing exercises. [step] These will get you ready to stretch out your body in the variety of poses you'll use to exercise your chest. Notice your breathing pattern as complete the mountain pose. <sep> (A) Inhale and keep your breathing slow and even throughout the whole warm up period. [substeps] Alternatively, do a crossfit pose to warm up. (B) [substeps] You might try taking an extended pause to " use " your rib cage, start to breath in, breathe out, and repeat. You can also try practicing your opening pose from a hovering yoga chair, at home, or in a pose at your workplace. (C) Settle on a consistent, slow pattern of breath as you start the workout. This breathing pattern will help calm yourself and prepare your heart rate for the more difficult exercises to come. (D) [substeps] After doing the mountain pose, you can do finger circles or kangaroo standing pose to warm up the muscles in your chest. [title] Do the rock dii to strengthen the core.

Ex Output:
C

Ex Input:
A man is seated in front of a small canvas. he <sep> (A) is showing exercises on how to use a paint roller. (B) picks up a brush and begins painting his brush. (C) is painted in a colorful pattern. (D) uses a long pointed brush to create an image.

Ex Output:
D