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: What are produced in both the male and female reproductive systems in humans?  
 (A) sperm (B) nutrients (C) fertilized eggs (D) sex cells

SOLUTION: D

PROBLEM: Which of the following was invented by Benjamin Franklin?  
 (A) bifocal lens (B) telescope lens (C) telephone (D) camera

SOLUTION: A

PROBLEM: After a rainfall, which process in the water cycle draws the water back up into the air?  
 (A) condensation (B) evaporation (C) circulation (D) precipitation

SOLUTION:
B