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". 

Example Input: [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.
Example Output: A

Example Input: Two young children come down the slope in red and black tubes. They come down steadily and smoothly till they reach the bottom of the slope. there <sep> (A) are some other people climbing up the slope with tubes and sledges in their hands. (B) are some people standing near a water drop holding tubes. (C) they sit on the rails and wait for the lift to come before they get off the roller coaster. (D) is an interview with a reporter from the tv station and a news station talking about mountainous terrain and the people who are climbing to the bottom of the hill.
Example Output: A

Example Input: [header] How to use a travel pillow [title] Try your neck pillow before buying it. [step] Neck pillows don't typically come in different sizes, so the only way to know if it will fit comfortably is to try it on. If possible, put your neck pillow on before you buy it, or keep the receipt and try it on before your trip. <sep> (A) [substeps] If you can't find your neck pillow online, contact the nearest travel store. Remember to wear a face mask to protect your neck body from respiratory and heart disease. (B) Here's how to write your partner's name on your neck pillow : [substeps] If the pillow you're sleeping on doesn't fit your neck pillow correctly, you can simply write down the name first. [title] Pick a traditional line or pattern to write in. (C) You should be able to rest your head on it without bending your neck uncomfortably, and the material shouldn't pinch or chafe on your neck. [title] Inflate your pillow if necessary. (D) [title] Buy a pillow with a stock head. [step] If you plan to travel with the stuffed stuffed topic on your pillow, opt for a head that can fit into the pillow.
Example Output:
C