You are given a science question (hard-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]: A student gives a red toy car a push on a wooden floor. The student then pushes the same red toy car on a cement floor. Which question is the student most likely investigating?  
 (A) How fast does a toy car usually roll? (B) What is the best way to make a toy car roll? (C) Which surface allows a toy car to roll farther? (D) Does color have an effect on the distance a toy car rolls?
[A]: C


[Q]: Biologists are studying the white-tailed deer population in Ohio. Which question could the biologists most likely answer?  
 (A) How fast does this deer population grow? (B) What percentage of people enjoy watching deer? (C) Does this deer population like warmer states? (D) Should people raise deer as pets?
[A]: A


[Q]: The primary cause of continental drift, earthquakes, and volcanic eruptions is  
 (A) convection currents beneath Earth's crust. (B) the rotation of Earth on its axis. (C) the gradual sinking of Earth's crust. (D) heat from the Sun warming Earth.
[A]:
A