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 get rid of the whitefly [title] Vacuum the flies. [step] Use a small hand vacuum, or hold the furniture-cleaning nozzle of a standard vacuum cleaner. Walk around your infested plants and suck the pests from the undersides of the leaves and foliage. <sep> (A) This method is quick and straightforward, and it can remove whiteflies from all stages of the development cycle-from larvae to mature, plant-munching adults. Vacuuming is most effective as soon as you notice an infestation. (B) [substeps] Lice/hornets that have infested the insect where possible will probably cause an infestation when they have access to this species. Lice and hornets can be pregnant bees or even cobwetters. (C) [substeps] Once you've vacuumed up all of the insects, you can dismantle the insect and wash it off. Plant diseases like freeze burn-gas are very likely to have mites, fungus, or other biological problems with this insect. (D) [substeps] If possible, clean the potted plants as a habit to keep the insects away. [title] Tear off the hard outer leaves once the insects have died.
A

We see an opening title screen. the man <sep> (A) applies blow to the hair he just sprayed. (B) puts an ice cream cone then eats it. (C) clamps his knees together and bends backwards. (D) then puts plaster on a base and applies it to the ceiling while on stilts.

D