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.

Which object is best used to demonstrate the bending of light as it passes through a substance?  
 (A) convex lens (B) flat mirror (C) opaque rod (D) concave mirror
A

A movie studio will use two methods of communication, television and the Internet, to advertise a new movie. Which of the following must both methods of communication use in order to show the advertisements to viewers around the world?  
 (A) systems to locate viewers (B) networks to transmit signals (C) printing to create the images (D) software to search for images
B

What causes a meteoroid to glow as it falls through the atmosphere of Earth?  
 (A) wind (B) gravity (C) friction (D) sunlight

C