Given the task definition and input, reply with output. In this task, you are given a multiple-choice question and you have to pick the correct option. Answer with option indexes (i.e., "A", "B", "C", and "D").

If a river is rushing southwest on a sunny day, then it is safe to assume that (A) southwest is a good place to be (B) the land gently inclines in that direction (C) the world is mostly land (D) the land is supple
B