Given the task definition and input, reply with output. 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.

Extensive folding of sedimentary rock layers on Earth provides indirect evidence of certain processes occurring throughout Earth's history. Which of these is most likely one of these processes?
(A) convective heat loss from Earth's mantle (B) slowing of the rotation of Earth's core (C) increase in the density of Earth's atmosphere (D) slow increase in the distance of Earth's orbit
A