Detailed Instructions: 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.
Q: A carpenter rubs sandpaper on a wooden bench to make the bench smoother. The sandpaper will get warm as it is rubbed on the bench. As a result of the friction between the sandpaper and the bench, thermal energy is converted to
(A) chemical energy that is stored by the sandpaper. (B) radiant energy that is transferred to the bench. (C) potential energy that is stored by the wood. (D) heat energy that is transferred to the air.
A:
D