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]: At what time on a sunny day will the shadow of the school's flagpole be the shortest?
(A) sunrise (B) noon (C) mid-afternoon (D) sunset
[EX A]: B

[EX Q]: Which of these elements is found in the greatest amount in organisms?
(A) carbon (B) iron (C) lead (D) neon
[EX A]: A

[EX Q]: How does ice change the shape of rocks?
(A) It dissolves the rocks by pooling on surfaces. (B) It breaks the rocks by expanding in openings. (C) It smooths the rocks by colliding with them. (D) It moves the rocks by pressing on them.
[EX A]:
B