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 relieve constipation after surgery [title] Use a stool softener. [step] One of the first medications to try if you're feeling constipated is a stool softener. These are easy to find over-the-counter and can help get you back on track. <sep> (A) [substeps] The way that stool softeners work is that they draw water into your stool from your intestines. This makes your stool softer and easier to pass. (B) [title] Take 600ml of stool softener before a meal. [step] Most stool softeners kill the production of prostaglandins. (C) [substeps] One good option for relieving constipation at the time of surgery is a stool softener. While stool softeners do provide temporary relief from constipation, they are expensive and will often disappoint you. (D) These medications are named for their antioxidant properties, which help reduce diarrhea and keep your stools from becoming irritated. [substeps] Remember that: the next time you're using an over the counter stool softener treatment, be sure to follow the dosing instructions.
A

[header] How to add umami to your cooking [title] Add cheese to pasta dishes and soups. [step] Parmesan has a salty, strong taste that only gets stronger with age. Add it to pasta sauces, either on top of the dish or into the sauce as it cooks, to create a deeper flavor. <sep> (A) [substeps] Add parmesan rinds to soups, like minestrone, to achieve the same effect. [title] Use anchovies to add the umami taste to a variety of dishes. (B) [substeps] You should add an even amount of cheese per dish (about 3/4 of this should always be grated). If adding it to pasta isn't convenient for you, get a handful of grated cheeses from the grocery store. (C) Consider adding of your own cheese, as italian dishes use tomatoes and other fruits to flavor an array of foods. Pair tomato slices with a wedge of cheese and other parmesan mixes in place of pasta, substitute cheese for pasta, or add more avocado or spicier additions. (D) [substeps] You can also add cheese on top of pasta dishes or soups. You can be creative and flavour your dishes using small amounts of cheese, but cheese is often the bread that goes with the pasta dish.

A