Are All Fungi Detrimental (Bad)for Other Organisms

Are all fungi detrimental (bad) for other organisms?

A) Yes-think of molds that destroy plant crops,or fungal infections that cause athlete's foot.All fungi are bad for organisms they colonize.
B) Yes-fungi feed directly on organic material (oftentimes killing it or feeding on it after the original organism has died) .As such,they are always bad for other organisms.
C) No-fungi are sometimes good,sometimes bad for other organisms.It really depends on which fungus you're talking about and the relationship it has with the other organism.Some fungi,for example,can form a symbiotic relationship with plant roots that increases their nutrient and water absorption.This is good.
D) No-fungi are ALWAYS good when they interact with other organisms.There's never a downside or negative aspect to such interactions.Both sides always benefit from the relationship.