TASK DEFINITION: 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.
PROBLEM: The weight of an object can change even when the mass stays the same. Which statement correctly identifies a relationship between mass and weight?  
 (A) The weight of an object depends on its mass and its volume. (B) Gravity affects the weight of an object but not its mass. (C) The mass of an object depends on its weight and size. (D) Magnetic fields can affect mass but not weight.

SOLUTION: B

PROBLEM: Many states require vehicles to be examined and to meet safety and pollution standards. What impact might vehicle inspections have on the environment?  
 (A) The environment will not be polluted. (B) The environment will become more polluted. (C) Fewer pollutants will be released by vehicles. (D) Fewer pollutants will be produced by older vehicles.

SOLUTION: C

PROBLEM: Which of the following is least likely to allow electricity to flow?  
 (A) aluminum (B) copper (C) plastic (D) water

SOLUTION:
C