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: Rich beds of marine fossils have been found in Florida. By dating these fossils, scientists can best determine
(A) when Florida collided with the North American continent. (B) the date when organisms moved onto dry land. (C) the period during which Florida was covered in water. (D) when the atmosphere of Earth was more humid than it is today.
A:
C