You are given a science question (hard-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]: An animal has six legs. What is it most likely to be?  
 (A) a spider (B) a fly (C) a lizard (D) a centipede
[EX A]: B

[EX Q]: Anna's class counted the number of butterflies in the school garden for an assignment. Anna's results were different from the rest of the class. What should she do?  
 (A) Change the assignment. (B) Leave the results alone. (C) Match her results with the class. (D) Ask the teacher to count for her.
[EX A]: B

[EX Q]: An engineering class has been instructed to develop a robot. The robot must be designed using electromagnetic energy as its only source of power. What topic is the engineering class most likely studying?  
 (A) the use of batteries and chemical energy (B) how radiant energy and solar collectors can be used (C) the conversion of kinetic energy to potential energy (D) how thermal energy can be converted into electrical energy
[EX A]:
B