instruction:
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". 
question:
[header] How to read a screw thread callout [title] Read the numbers. [step] They will look something like one of these : [substeps] 4-40 x. 5 1/4-20 x 5/8 m3-0.50 x 10 [title] Interpret the first number. [step] The first number gives the major, or largest, diameter. <sep> (A) Next, determine the size of the screw thread you wish to use. Write these numbers down on several pieces of paper and trace around them. (B) It also tells you the larger diameter of a screw thread to create a series of polygons which share a small degree of overlap by a single number. [title] Separate the single digits in each string from each string. (C) [substeps] In unified threads (measured in inches) there are numbered diameters 0 through 10, with 0 the smallest and 10 the largest. ( diameters 12 and 14 may also be found, but are usually on older equipment and needed for repairs or restorations. (D) However, an " x " will bring more light up on an empty needle, so use a tray or ice scraper to fill it to feel the thickness of the screw. The next number tells us that the machine is a small amount bigger or larger than what we used it for.
answer:
C


question:
[header] How to change trackpad settings on macbook pro [title] Find the system preferences. [step] Starting from your main desktop screen there are two ways to find the system preferences where the mouse and touchpad settings will be located : [title] Bring your cursor to the bottom screen and find the system preferences application. [step] The icon looks like a box with three gears inside it. <sep> (A) Open that to find all your system preferences. [substeps] Alternatively, you can use the spotlight feature. (B) On macbook pro this icon resembles a round blue square with a horizontal green dot on it. On other applications this icon is actually a box with a gear, and is small in appearance. (C) It can be located on the taskbar or in the upper left-hand corner of the window. [title] Let the system preferences application perform its work. (D) [title] Click the customize key in the dialog box. [title] Follow the on-screen instructions to change the customization function.
answer:
A


question:
[header] How to check lymph nodes [title] Locate your lymph nodes. [step] You have the highest concentration of lymph nodes in your neck, collarbone, armpits, and groin. Once you know where they are, you will be able to check them for pain or swelling. <sep> (A) [substeps] To identify your lymph nodes, look at your earlobe or high neck. To perform a blood test, attach a needle at the corresponding carotid artery. (B) [substeps] Identify them with an eye dropper or a syringe. The eye dropper or syringe should be attached by cord to a length of flexible metal tubing or cleat. (C) [substeps] There are other groups of lymph nodes throughout the body, including the inside of your elbows and knees, but these are not commonly checked for swelling. [title] Test an area with no lymph nodes for comparison. (D) Nodes can be found using this tool : [substeps] Find your very appropriate area of the neck. The most important areas are your lymph nodes, located across the top of your neck.
answer:

C