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". 

Input: Consider Input: [header] How to find the number of a blocked call [title] Get an private branch exchange (pbx) account. [step] One option is asterisk, a free, open source software. Another is switchvox. <sep> (A) This will also work better than 200 blackwire. If you buy one, it will work with the same account ($ 0.11). (B) The pbx is considered to be a free exchange. While this service typically does not have much use for a desktop account, it gives you access to many anonymous call accounts. (C) A pbx converts your computer into a telecommunications device and will allow you to manipulate incoming call data to identify blocked callers. [substeps] Before embarking on this method ensure that you thoroughly understand the technical challenge it presents and the potential financial burden it incurs. (D) Without switchvox here you are on better business. No other option is available to get a contact number from an online website.

Output: C


Input: Consider Input: [header] How to avoid the stomach flu [title] Wash your hands often. [step] Wash your hands carefully with soap and water for at least 20 seconds. Always wash your hands after going to the washroom and before and after handling food and eating. <sep> (A) Washing your hands is important, since if the way you handle and eat is bad (germs, bacteria, etc. ), your best chance at preventing the flu is by keeping your hands clean. (B) Don't attempt to dry or clean your hands on something other than a business table. [title] Wear long pants (not utility pants to wear running shoes with). (C) [substeps] It's a good idea to wash your hands between-and as many times as you go to the bathroom. This will help prevent an episode of nausea in the future, as well as allow your body time to shut down its internal defenses to fight off food, germs, and viruses. (D) This will help to prevent the spread of germs. Germs on your hands can get into your eyes, ears, and nose and make you sick.

Output: D


Input: Consider Input: [header] How to buy an ink cartridge [title] Look online. [step] On-line ink stores can also be a time saver, allowing you to look at your printer from home to insure that you purchase the correct cartridge. [title] Consider name products or compatible products. <sep> (A) [step] For simple print printing, it's vital that manufacturers explain each brand. But printing on a brand name section may simplify editing. (B) [step] If you want a brand name ink cartridge, you should opt for specific brand names. For example, colorlers and printers might want a name brand ink-bottomed printer with ink cartridges that are compatible with their computers. (C) [step] Discount ink and toner cartridges allow you to save money printing at home while getting high quality print outs. While most discount printer ink cartridges are of good quality, there are exceptions and quality will vary. (D) [step] If you're buying a watercolor cartridge for a gun or awning, you will probably want a different name than using the same one over and over. There are a number of different brands, including cakeshop, watercraft, and line.


Output: C