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.
--------
Question: 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

Answer: C


Question: Which of the following best describes an advantage of using a mass production manufacturing system instead of a custom manufacturing system?  
 (A) Customers can provide specific feedback to workers. (B) Workers become skilled in all aspects of assembly. (C) Goods can be easily modified for customers. (D) Products can be made at a lower cost.

Answer: D


Question: A scientist wants to collect several bird eggs on an island. She needs a case that will protect the eggs she collects. Which of the following cases would best protect the eggs?  
 (A) a hard metal case with flexible foam lining (B) a flexible metal case with smooth plastic lining (C) a strong wooden case with lightweight plastic lining (D) a lightweight wooden case with strong aluminum lining

Answer:
A