instruction:
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.
question:
Proxima Centauri is the closest star to the Sun. Which units do astronomers most often use for the distance between Earth and Proxima Centauri?  
 (A) miles (B) meters (C) light years (D) astronomical units
answer:
C


question:
The change in fur color of the Arctic hare from brown in the summer to white in the winter is an example of  
 (A) mimicry. (B) heredity. (C) diversity. (D) camouflage.
answer:
D


question:
A birdwatcher wants to identify an eastern bluebird. What feature of a bird should the birdwatcher evaluate first to identify an eastern bluebird?  
 (A) beak shape (B) eye position (C) feather pattern (D) tail-feather length
answer:

C