I think that the answer is B, but I may be wrong...
Trees and forest play an important role in balancing the amount of Carbon in the atmosphere through the process of photosynthesis where plants make their own food with carbon dioxide, using energy from the sunlight. Therefore, deforestation (cutting down of trees) has an effect on the carbon cycle also the greenhouse gas effect and global warming. Deforestation reduces the removal component of this cycle, thus, increasing the carbon dioxide in the air.
