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".
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Question: [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.

Answer: C

Question: [header] How to make green enchiladas [title] Wash the chicken. [step] Rinse each chicken part thoroughly in cool water, then pat them dry with paper towels. [title] Poach the chicken. <sep> (A) [step] Cut the chicken in half, then run a slotted spoon along the sides to allow the chicken to cook evenly. Poach for half an hour, or until the chicken is tender and no longer have its skin burned. (B) [step] Melt the olive oil in a saucepan over medium heat, then add the chicken, poaching mixture and poaching water. Use a wooden spoon to stir well, then place the chicken in the oven. (C) [step] Place the chicken pieces in a large pot. Cover with an inch of water and sprinkle in a teaspoon of salt. (D) [step] You'll need about 8 tbsp. ( 240 ml) of chicken fat, since it will cook in the broth.

Answer: C

Question: The machine is shown moving on its own. One of the individuals plays table tennis with the machine. a small boy <sep> (A) plays table tennis with the machine as others watch on. (B) is shown when the machine stops, and they continue playing. (C) is shown scoring a point across the screen. (D) twirls on the table muscle over and over.

Answer:
A