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.

[EX Q]: A leaf is covered in mud during a landslide. After one million years, this leaf will most likely be ___.  
 (A) a fossil (B) an animal species (C) a new plant species (D) a nonrenewable fuel
[EX A]: A

[EX Q]: Electron transport in mitochondria results in a chemiosmotic gradient of which particle across the mitochondrial membrane?  
 (A) ADP (B) ATP (C) protons (D) neutrons
[EX A]: C

[EX Q]: What do playing a guitar, banging a drum, and dropping a pebble in the water have in common?  
 (A) They all produce light. (B) They all cause vibrations. (C) They all convert heat to energy. (D) They all need gravity to move.
[EX A]:
B