Detailed Instructions: 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").
Problem:Where would rocks be the smoothest? (A) where thunder was heard (B) where water has flowed for years (C) where wind has blown for days (D) where the human population is the highest
Solution:
B