Given the task definition and input, reply with output. 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 reverse tooth decay [title] Brush your teeth twice per day. [step] Regular daily brushing is crucial for maintaining good dental health and it may also help to reverse the decay process. Make sure that you brush your teeth at least twice per day, such as in the morning and before you go to bed. <sep> (A) [substeps] You should avoid using a toothpaste that contains fluoride. Toothpaste containing fluoride will increase the risk of tooth decay. (B) [substeps] Choose a toothpaste that contains fluoride. Fluoride is necessary for remineralizing teeth and reversing tooth decay. (C) This should help to prevent them from becoming overgrown. [title] Use a soft bristled toothbrush. (D) Stop at the halfway point of your brushing routine and don't forget to brush for a few seconds and then rinse your mouth. [substeps] Brushing is especially important during the daytime when you're traveling or if your periodontal infections or fever are prevalent.
B