Given the task definition and input, reply with output. 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.

Which example shows a new substance being formed?  
 (A) a candle burning (B) a shoelace being tied (C) a pipe being cut in half (D) a block of ice melting

A