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.

[EX Q]: 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
[EX A]: B

[EX Q]: In a classroom demonstration, a teacher pours sulfuric acid on some granulated sugar in a beaker. The sugar turns yellow and then black. Smoke rises and a strong smell is released. This demonstration is an example of what kind of change?  
 (A) chemical (B) physical (C) magnetic (D) electric
[EX A]: A

[EX Q]: Students wanted to see if the growth of a plant was affected by using four different types of soil. How should the students best carry out this investigation after potting the plants in the four different types of soil?  
 (A) observe the plants and record observations daily (B) move the plants to new locations every day (C) measure the height of each plant every hour (D) add different amounts of water to each plant
[EX A]:
A