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.
--------
Question: When oxygen combines with hydrogen, which substance is formed?  
 (A) water (B) vinegar (C) hydrochloric acid (D) hydrogen dioxide

Answer: A


Question: A cut to the skin is treated with antiseptic first to avoid  
 (A) an immune response. (B) a bacterial infection. (C) bruising of tissues. (D) an allergic reaction.

Answer: B


Question: The movement of crustal plates results from circulating currents in material beneath the crust of Earth. Which best describes the material which moves the crustal plates?  
 (A) hot water (B) molten rock (C) liquid metal (D) solid iron

Answer:
B