TASK DEFINITION: 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.
PROBLEM: Sam looks into a fish pond and points at a goldfish. Sam's grandfather looks where Sam is pointing and tells Sam that the fish is actually in a different location. Which property of light explains why Sam's grandfather is correct?  
 (A) reflection (B) refraction (C) diffraction (D) absorption

SOLUTION: B

PROBLEM: What type of force keeps the planets orbiting the Sun?  
 (A) gravitational (B) magnetic (C) electrical (D) nuclear

SOLUTION: A

PROBLEM: Which statement about all living organisms is true?  
 (A) They have limbs. (B) They produce their own food. (C) They breathe air. (D) They have at least one cell.

SOLUTION:
D