You are given a science question (easy-level) and four answer options (associated with "A", "B", "C", "D"). Your task is to find the correct answer based on scientific facts, knowledge, and reasoning. Do not generate anything else apart from one of the following characters: 'A', 'B, 'C', 'D'. There is only one correct answer for each question.
Q: Students on a field trip discovered fossilized shark teeth on the side of a cliff. Which conclusion can best be made about the history of the area?
(A) It was once a hot desert. (B) It was once a shallow sea. (C) It was once part of a glacier. (D) It was once part of a rain forest.
A:
B