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.

Example Input: Which is a renewable resource?  
 (A) oil (B) coal (C) trees (D) aluminum
Example Output: C

Example Input: Scientists found a new species of a complex organism at the bottom of the ocean. The organism most likely  
 (A) is unicellular. (B) is a form of bacteria. (C) is made of multiple cells. (D) lacks an organized nucleus.
Example Output: C

Example Input: Which of these objects will most likely float in water?  
 (A) glass marble (B) steel ball (C) hard rubber ball (D) table tennis ball
Example Output:
D