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 Input:
Which of the following properties best describes a material's ability to resist scratching?
(A) weight (B) flexibility (C) length (D) hardness

Ex Output:
D

Ex Input:
Which is a trait that a child can inherit from its parents?
(A) eye color (B) a broken leg (C) length of hair (D) language skills

Ex Output:
A

Ex Input:
Homes that are built to be environmentally friendly because they use energy more efficiently than other homes are called "green" homes. "Green" homes often have reflective roofs and walls made of recycled materials. The windows in these energy-saving homes are double-paned, meaning each window has two pieces of glass. Double-paned windows have a layer of air between the window panes. This layer is a barrier against extreme temperatures and saves energy. A solar panel on a "green" home uses
(A) chemical energy (B) mechanical energy (C) a renewable energy source (D) a nonrenewable energy source

Ex Output:
C