instruction:
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:
Andre learned that plants survive through a process called photosynthesis. Which substance do plants produce during photosynthesis?  
 (A) minerals (B) nitrogen (C) soil (D) sugar
answer:
D


question:
A student examines a new watch design. The watch has a small solar cell on its face. The main function of the solar cell is to  
 (A) reduce the cost of the watch. (B) provide an energy source for the watch. (C) make the watch more attractive. (D) stop the watch from speeding up.
answer:
B


question:
In Colonial America, people used ice to help keep foods fresh. They cut the ice from lakes and ponds during the winter and stored the ice in ice houses. They sometimes used hay as an insulator to prevent the ice from melting. If you wanted to build an icehouse today, which of the following would be the best material to use as an insulator?  
 (A) dried leaves (B) foam blocks (C) plastic wrap (D) rock salt
answer:

B