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 is mixing a cup of hot chocolate with a spoon. How is the heat transferred between the hot chocolate and the part of the spoon that is in the hot chocolate?
(A) Conduction transfers energy from the spoon to the hot chocolate. (B) Conduction transfers energy from the hot chocolate to the spoon. (C) Convection transfers energy from the spoon to the hot chocolate. (D) Convection transfers energy from the hot chocolate to the spoon.
[A]: B

[Q]: Many scientists think that burning fossil fuels has increased the amount of carbon dioxide in the atmosphere. What effect would the increase of carbon dioxide most likely have on the planet?
(A) a cooler climate (B) a warmer climate (C) lower relative humidity (D) more ozone in the atmosphere
[A]: B

[Q]: Which nongaseous compound can be made from two elements that are gases at room temperature?
(A) water (B) table salt (C) iron oxide (D) carbon dioxide
[A]:
A