You are given a science question (easy-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]: What is a common use of the mineral graphite?  
 (A) to make glass (B) as a source of iron (C) to make pencil leads (D) as a household cleaner
[A]: C


[Q]: When the cardboard cone of a radio speaker vibrates, it produces a sound in the air around it. The cone produces this sound by transferring which of the following to the air around it?  
 (A) heat (B) current (C) wave motion (D) magnetic force
[A]: C


[Q]: Students are learning about the natural resources in Maryland. One group of students researches information about renewable natural resources in the state. The other group researches information about nonrenewable natural resources in the state. The resources the students investigate include plants, animals, soil, minerals, water, coal, and oil. Aluminum is a nonrenewable natural resource. Which of these methods of aluminum disposal is best for the environment?  
 (A) burning it (B) recycling it (C) burying it in landfills (D) crushing it before throwing it away
[A]:
B