Q: 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 measure and buy the correct bike [title] Buy a road bike if you plan to ride primarily on pavement. [step] There are a lot of different types of road bikes available for different styles and functions. They are all, however, made for generally even, hard terrain like city roads or smooth trails. <sep> (A) [substeps] Know your model before buying a bike if you want to avoid looking for a new one. Buy an off-road bike because that's what the bicycle pack includes, rather than a road bike you'll need right on the spot. (B) The most popular choice is a road bike-a road bike with a sturdy and narrow rear (linear) seat. Bike versions are equivalent to a classroom class bike, but they also come with the upper frame to simulate conditions. (C) They are the most common bikes out there, and can be broken up into a few subcategories : [substeps] Racing/road bikes: aerodynamic, fast, and light, these bikes are the most common road warriors. They have thin tires and lighter frames, and usually aren't made to carry extra weight. (D) Other options include river-track sites, stream-pool sites, and creek track. [substeps] Even if you will not ride on a road or stream, if you or your friends have an mi bike or other important bike element, buying a road bike makes the process much more as well.
A:
C