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:
Compared to Earth, the Moon is  
 (A) drier. (B) larger. (C) heavier. (D) brighter.
answer:
A


question:
The shape of a riverbed changes over time as a result of which gradual process?  
 (A) erosion (B) dissolving (C) plate shifting (D) compaction
answer:
A


question:
What carries oxygen throughout the body?  
 (A) white blood cells (B) brain (C) red blood cells (D) nerves
answer:

C