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.

[Q]: Which of the following units best represents the density of an object?  
 (A) kg (B) hr (C) m/s^2 (D) g/cm^3
[A]: D


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


[Q]: In the human body the digestion of proteins takes place primarily in which two organs?  
 (A) Mouth and stomach (B) Stomach and small intestine (C) Liver and gall bladder (D) Pancreas and large intestine
[A]:
B