Answer:
The right answer is B) decomposition
Step-by-step explanation:
Elements like carbon and nitrogen are major constituents of living structures (cell membarnes, proteins, carbohidrates, etc). These elements are incorporated in living structures through metabolism. Structures containing carbon and nitrogen can enter soil from excretes, dead matter and other sources and will experience a process called decomposition, by which microorganisms reduce structures in its components (carbon and nitrogen for expample) and released them.