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: Which of these activities is used to conserve water?  
 (A) planting crops that survive in droughts (B) running water while brushing teeth (C) washing vehicles frequently (D) watering grass after a rainfall

SOLUTION: A

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 statement best describes a liquid sample?  
 (A) It will retain its volume if transferred to a larger container. (B) It keeps its shape when transferred to a larger container. (C) Its volume can be greatly reduced by adding pressure. (D) Its shape can be changed by increasing its temperature.

SOLUTION:
A