Why are fungi so important to the carbon cycle?

a.) Fungi produce O2 and make it available to nearby plants for use in the carbon cycle.
b.) Fungi release water from the soil and break it up into its constituent elements, thus freeing up hydrogen atoms for the carbon cycle.
c.) Fungi accelerate the carbon cycle by breaking down wood and thus freeing up carbon atoms.
d.) Fungi fix carbon and produce O2 just like plants do during photosynthesis.