Q: 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").
A woman is digging under a tree on a tall mountain. She is looking for interesting rocks, and a foot down into the soil, discovers a fossilized fish skeleton. From this discovery, the woman is able to determine that (A) the mountain used to be underwater (B) some bears in mountains eat fish (C) some fish can climb mountains (D) sometimes rain can move fish to high spaces
A:
A