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.
One example is below.
Q: Which part of a bicycle BEST moves in a circle? 
 (A) Seat (B) Frame (C) Foot pedal (D) Kickstand
A: C
Rationale: Seat, frame and Kickstand are static parts of the bicycle, even when bicycle moves. Foot pedal moves in a circle as bicycle moves.
Q: Which of these describes a chemical change?  
 (A) water freezing (B) paper burning (C) water becoming steam (D) paper being torn
A:
B