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: An introduction comes onto the screen for a video about rock climbing and a man introduces what will happen in the video. a men in a blue shirt <sep> (A) is doing a jump and falling off, then he begins to climb along the rock face with another by him. (B) stands behind a rock wall talking. (C) is shown climbing all the way to the top of a rock. (D) and the interviewer is inside of a gate in a park and he begins by jumping up to the top of a roofed wooden fence to do various things.

A: C
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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
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Q: [header] How to tell the difference between different types of plant fertilizers [title] Use soluble fertilizer when you want to water in the fertilizer. [step] This fertilizer is usually added to the watering can. [substeps] This is best for helping boost growth when its growing season and for frequently fed container plants. <sep> (A) In the summer break, try adding two or three inches of food to fill the watering can-too much fertilizer will kick in when the corn is thirsty, too little will only keep it growing. Plan it out in a bucket or basin for easy irrigation. (B) [title] Use a hose to water a potted plant after planting. [step] Water a cactus when they get too hot for watering. (C) Leaves that don't bond and stink up the water are also large fertilizer that needs to be added to your watering can. [title] Use different types of fertilizer. (D) [title] Use granular fertilizer when you need to supply a concentrated amount of nutrients. [step] A plant may be lacking in a particular nutrient (this will be evident through such things as yellow leaves, , etc.

A:
D
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