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.

[EX Q]: The best example of balanced forces is a
(A) car increasing speed. (B) bus parked in a garage. (C) ball kicked along a flat surface. (D) roller coaster slowing down on an incline.
[EX A]: B

[EX Q]: Manuel wants an area in the yard to wash the dog without making mud puddles. He wants to put something on the ground that water passes through easily. Which of these materials would be the best for him to use?
(A) clay (B) plastic (C) soil (D) pebbles
[EX A]: D

[EX Q]: How do the sprouts of seeds buried in complete dark in the soil find their way to the surface of the soil?
(A) They grow toward light. (B) They grow toward surface warmth. (C) They grow opposite the direction of the bedrock. (D) They grow opposite the direction of the pull of gravity.
[EX A]:
D