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]: Some scientists predict that as greenhouse gases change the climate of Earth, the number and strength of hurricanes will increase. In order for this to occur, the climate change would have to affect Earth by changing the  
 (A) depths of the oceans. (B) speed of currents in the oceans. (C) chemical compositions of the oceans. (D) amount of dissolved oxygen in the oceans.
[A]: B


[Q]: Of these research projects, which is the best choice for a student who is interested in environmental issues to study?  
 (A) making cars run on less fuel (B) finding more sites for copper mines (C) making ocean liners bigger and faster (D) replacing human workers with robots
[A]: A


[Q]: How are the particles in a block of iron affected when the block is melted?  
 (A) The particles gain mass. (B) The particles contain less energy. (C) The particles move more rapidly. (D) The particles increase in volume.
[A]:
C