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 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.
[EX A]: B

[EX Q]: Which statement about plant and animals cells is true?  
 (A) Both have a cell wall to give them support. (B) Both have a large vacuole to store water. (C) Both use mitochondria to produce energy. (D) Both use chloroplasts to store energy.
[EX A]: C

[EX Q]: Eagles have strong, sharp beaks that are most likely adapted for the eagle to eat  
 (A) fish. (B) eggs. (C) worms. (D) flowers.
[EX A]:
A