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: As a car burns fuel, a transformation from chemical to mechanical energy takes place. What is the most likely result of the fuel burning?  
 (A) The matter that makes up the car increases. (B) The amount of useful energy decreases. (C) The efficiency of the car increases. (D) The amount of heat energy decreases.

A: B
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Q: What circuit does not allow an electrical current to flow through it?  
 (A) closed (B) open (C) parallel (D) series

A: B
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Q: What is the main energy source for deep ocean currents that move large volumes of water around the planet?  
 (A) heat from Earth's core (B) radiation from the Sun (C) tidal effects of the Moon (D) motion of tectonic plates

A:
B
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