Sacculina carcini is a barnacle that attaches to the underside of the green crab. The barnacle finds a hole in the green crab's exoskeleton, then uses microscopic hairs to feed on nutrients from the green crab's blood. The barnacle also lays it eggs in the green crab reproductive system, which sterilizes the green crab.
Which term describes the role of sacculina carcini in the this relationship?
a. prey
b. host
c. parasite
d. predator