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.
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Question: Which of the following compounds is most likely to be part of living organisms?
(A) C?H??O? (B) BF? (C) MoCl? (D) CsI

Answer: A

Question: Which of the following units best represents the density of an object?
(A) kg (B) hr (C) m/s^2 (D) g/cm^3

Answer: D

Question: Which items would best protect a group of students while investigating a forest ecosystem?
(A) short pants and T-shirts (B) short pants and long-sleeved shirts (C) long pants and T-shirts (D) long pants and long-sleeved shirts

Answer:
D