Detailed Instructions: 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.
See one example below:
Problem: Which event can cause a large rock to become soil over time? 
 (A) decaying (B) an earthquake (C) a landslide (D) weathering
Solution: D
Explanation: Under the action of heat, cold, rain, wind, and other atmospheric factors, the rock breaks down physically into small fragments that become the parent material of the soil. Also, atmospheric factors change according to weather.

Problem: During which activity should a student wear a laboratory apron or coat?  
 (A) cracking open a geode (B) adjusting a microscope (C) spraying water on plants (D) adding salt to boiling water
Solution:
D