Answer:
Parasitism
Explanation:
Parasitism may be defined as a biological interaction in which one organism (parasite) lives on the body of other organism (host). The parasite can directly obtained ready-made food from the host.
Lamprey attaches with another fish , can directly obtain nutrient and may cause harm to fish. Here, lamprey is parasite and the fish acts as a host for lamprey.
Thus, the correct answer is option (b).