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.

What is the most important way an artificial reef, such as a sunken ship or railroad car, may support the development of a complex ecosystem?  
 (A) by providing habitat for large fish and plants (B) by providing habitat for algae and small invertebrates (C) by providing habitat for marine mammals and plants (D) by providing habitat for bacteria and fungi

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
B