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.

[EX Q]: A snail's shell provides the snail with  
 (A) food. (B) energy. (C) protection. (D) transportation.
[EX A]: C

[EX Q]: During a biochemical reaction, pyruvate (C3H4O3) is converted into carbon dioxide (CO2) and water (H2O). In what cellular organelle does this biochemical reaction occur?  
 (A) nucleus (B) cytoplasm (C) mitochondria (D) endoplasmic reticulum
[EX A]: C

[EX Q]: Which of these cell types has DNA that is not bound in a nuclear membrane?  
 (A) a plant cell (B) a protist cell (C) an animal cell (D) a prokaryote cell
[EX A]:
D

