You are given a science question (hard-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]: Which of these do all cells release?  
 (A) sugar (B) water (C) energy (D) oxygen
[EX A]: C

[EX Q]: A gene mutates in a type of bacteria. When these bacteria reproduce asexually, this mutation can only be inherited by  
 (A) different types of bacteria. (B) cells in the bacteria that are non-reproductive. (C) bacteria cells that are missing the gene. (D) direct descendants of the bacteria.
[EX A]: D

[EX Q]: Which action creates competition between environmental concerns and economic gains?  
 (A) protecting endangered wildlife (B) reintroducing wildlife into their natural habitats (C) using forest land to build homes (D) using city buses for transportation
[EX A]:
C