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".

[Q]: [header] How to polish rocks [title] Choose the right rock. [step] You can polish any stone you wish, but there are certain characteristics of a stone that will make it easier to polish. If you want an easy stone to polish, pick a somewhat softer stone like onyx, limestone or calcite. <sep> (A) [substeps] You can polish diamond, granite or ceramic stones by cutting thin pipe holes or inserting dry mortar into one side of each hole. Look for a stone that resembles a diamond, but not necessarily a diamond. (B) Otherwise, a smoother, more pumice-like stone will be more difficult to polish. [substeps] Emeralds and equilateral manganese are both excellent mineral polishes. (C) Stones that are very hard will take a much longer time to polish. However, though hard rocks take a long time to sand, they yield more shine than softer rocks. (D) Softer rocks will actually work more well, and might look better to polish very old stones, but brighter stones tend to chip quicker. [substeps] Rubies, sapphires, and emerald are good options.
[A]: C

[Q]: He heats up some cream and chops up the porcini mushrooms to add to the cream with some seasonings. He adds some cooked pasta into the porcini sauce with some reserved pasta liquid. he <sep> (A) adds salt to the sauce and adds some corn syrup. (B) applies seasonings to the pasta as well as adds some french dressing and easily cooks. (C) serves up the dish on a plate and tastes it. (D) completes the salad with other ingredients and this time stirs them by adding salt and a little bit of garlic on the side of the pasta.
[A]: C

[Q]: [header] How to make a homemade (natural) protein hair mask [title] Mix the egg yolk and yogurt. [step] In a small bowl, beat the yolk from 1 egg. Next, add 6 tablespoons of plain yogurt, and use a spoon to mix until the ingredients are fully combined. <sep> (A) [title] Add the rest of the ingredients, except for the milk and oil. [step] Once the amount of ingredients have been mixed, mix in approximately 2 egg yolks. (B) [title] Combine the walnuts and coconut oil. [step] Pour the mashed walnuts and coconut oil into a separate bowl and place it in the electric mixer with the speed dial on medium for about 3 minutes. (C) Place the mixture into a pan on medium heat and cook, stirring occasionally. [substeps] When the egg yolk mixture comes to a boil, stir in 2 tablespoons of powdered sugar. (D) [substeps] Egg yolk is rich in proteins and fats, so it helps strengthen and moisturize dry, brittle hair. In addition to protein, yogurt contains lactic acid, which helps remove dirt and product buildup while also moisturizing the hair.
[A]:
D