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 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.
C

[header] How to buy common stock [title] Find an online broker. [step] The easiest way to work with a broker today is online. You'll open an account with the broker and then deposit money into the account. <sep> (A) When you receive money back, you can make your payments without a current account. Brokers are licensed to do large, complex transactions, so don't hesitate to go to a broker if you are buying large amounts of stock. (B) Then you can search online for those stocks you're interested in investing in. [substeps] Some financial brokers you may consider are miller, a&m, airchat, and bankrise. (C) You can find online brokers by searching online. Some of the more popular include the following : [substeps] Charles schwab e * trade td ameritrade optionshouse [title] Identify if you want a full-service broker instead. (D) Most brokers offer deals to you either on your own or at low interest rates. However, if you don't have an online broker, you should look at a few online brokerages in your area.
C

People are strapping on these qloja machines to their feet. It takes a pretty long time to get them on and then they start to walk. they <sep> (A) are really excited and ready to get on the machine so they taken off like they were walking on their own machines. (B) don't bend down very far at all, they just get on them and bounce around. (C) build up a little speed and start kind of running in a line. (D) start to go in circles and then the machine starts to look very unstable, you know it hurts pretty much the whole time.
C