Answer:
The correct answer I believe would be C
Step-by-step explanation:
This question can be solved by using the process of elimination.
As it states in the paragraph, we are looking at the mutualistic relationship of the two fungi. For an organic relationship to be mutualistic, both organisms must provide a service that aids the other, this is why C is the best possible answer; both organisms provide a service that benefits them both and help their continuation of growth.
Hope this helps :)