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 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.
C

[header] How to make healthy mashed potatoes [title] Wash and cut the potatoes. [step] Wash 1 1/4 pounds (567 g) of your potatoes. You can also use a mix of potatoes and root vegetables for a variety of nutrients. <sep> (A) You can discard the peels, pits, and skins to make only healthy mashed potatoes. [substeps] The mashed potatoes will have a mildly sour texture after this step. (B) Leave the skin on the vegetables and cut them into 1-inch (2.5 cm) pieces. [substeps] Ensure that the pieces are the same size, so they cook evenly. (C) Wash the potatoes out of a colander and rinse them under clean running water. Then rinse each potato under cool, running water for about 5 seconds to remove dirt. (D) Wash the potatoes under hot tap water so they're soft and ready to eat. [substeps] Fresh or frozen mashed potatoes will last 7 to 10 months.
B

[header] How to go dairy free and stay healthy [title] Make changes to your diet slowly. [step] Start by making small changes to your diet, removing dairy slowly and over time. By making small changes that you can live with, you will find it easier to sustain this new diet that you are implementing. <sep> (A) [substeps] The purpose of these changes is to reduce your current sugar intake or processed food consumption, so don't put the drastic changes in your diet into perspective. If you go dairy free, you'll start not eating or making overly processed foods. (B) This will help to motivate you to start eating healthier. [substeps] You may need some additional input of what you should change every day. (C) [substeps] Don't start a new diet that increases your risk for developing some form of obesity. This can reduce your metabolism and enables you to control your weight. (D) [substeps] By gradually decreasing your consumption of dairy products, cravings may not be as intense. If you are already aware of the dairy products you currently consume, remove the dairy products that you can live without.
D