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". 

[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.
D

[header] How to make eyeliner wings even [title] Cut off two small pieces of tape. [step] You can use household scotch tape, or you can use surgical tape if your skin is a bit more sensitive. You will need one small piece for each eye. <sep> (A) You can always use 24 to 48 segments of duct tape if you want to make more liner. [substeps] Keep in mind that your wings might start to go out of style once the tape has dried. (B) [title] Use your tweezers to prick each eye in the " c " shape using the scratch tool. [step] Each eye needs to be in roughly the same shape, preferably with parts without movement. (C) [title] Make two smaller butterfly-shaped lines with the tape : [step] You can make a smaller butterfly-shaped wing by cutting it in half. Before you brush it over your face, wind it around your nostrils to make one side longer. (D) Fold one corner of the tape down, so that it creates a little flap that will make it easier to peel the tape off of your skin. [title] Place the tape on the corners of your eyes.
D

[header] How to tell when you are straining your eyes [title] Check for sore, tired, burning or itching eyes. [step] If your eyes start to itch, burn or get tired, this might be a symptom of eye strain. Keeping your eyes focused for long periods of time at the same distance can sometimes cause eye fatigue. <sep> (A) [title] Determine if you have eye strain while sleeping. [step] A sore eye might be caused by allergies to a variety of allergens. (B) [substeps] People with eye strain often have puffy eyes. [title] Check for allergies to irritants. (C) If this happens, take a break from what you're doing. A damp washcloth laid over the eyes may help relieve the discomfort. (D) Check for retinal and cancerous conditions such as horn inflammation, in which case you may need additional prescription eye drops. Common eye infections can be caused by bacteria, viruses, and other pathogens, though they are rarely very serious.

C