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 be a good mathematician [title] Develop your interest in high school. [step] Maybe you have always been fascinated by numbers and how formulas explain the world in which we live. If you think mathematics might be something you want to pursue further, focus on your math courses in high school. <sep> (A) [substeps] Ask your teachers for extracurricular activities you can participate in to hone your math skills, such as quiz bowl or mathletes. Compete in mathematics competitions such as the international mathematical olympiad. (B) Planning out your computer classroom will help you to focus on it at the very least as you educate yourself. You can attend primary school pe courses, but if you have college, you can take math courses. (C) Being a teenager doesn't mean you have to get a high school diploma to be a good mathematician. It is only a small stepping stone into a good career. (D) It's not too hard to acquire the necessary interest to get you started. You can also really look in to the focus specific to math in high school.

A