Many Species of Parrotfishes Inhabit Coral Reefs

Many species of parrotfishes inhabit coral reefs.These species have different feeding habits, swimming in and around the corals.Many large species, such as steephead parrotfish, feed by scraping algae from the substrate of the coral reef, exposing bare areas where new coral larvae can settle.Others, such as bumphead parrotfish, actually eat the coral, taking large bites from the coral skeleton and damaging its integrity, so it takes years to repair.How can these interactions best be characterized?

A) Both are mutualisms because both fish live and depend on the coral reef, and corals benefit from both.
B) Both are commensalisms because both fish live and depend on the coral reef, but corals are not affected by them.
C) The steephead-coral relationship is a mutualism because both species benefit; the bumphead-coral relationship is a predator-prey relationship, as the fish kills or damages the coral.
D) The steephead-coral relationship is a mutualism because both species benefit; the bumphead-coral relationship is a commensalism because the bumphead benefits without harming the coral.
E) The steephead-coral relationship is a commensalism because the steephead receives food; the bumphead-coral relationship is a mutualism because both species benefit.