Answer:
A. Over millions of years, the decaying vegetation would have been buried and its carbon turned into fossil fuels.
Step-by-step explanation:
This is the most accurate description of how the collapse of the Carboniferous rainforests have affected the Earth's carbon cycle. Fossil fuels are the result of the anaerobic decomposition of vegetation that died and sedimented in large quantities. This occurred millions of years ago, and thanks to high levels of heat and pressure the organic matter was chemically altered, resulting in the creation of fossil fuels.