Answer:
The correct answer would be B. It is a tertiary consumer because most of the things it eats are secondary producers.
In a food chain or web, the tertiary consumers are those which can consume primary as well as secondary consumers.
They are either carnivores, that is, meat eater or omnivores, that is, those who consume both plants as well as animals.
Similarly, orange roughy fish consume organisms like squid which is itself a secondary or tertiary consumer in a food chain. It can also consume small fishes which are primary consumers in a food chain.
Thus, orange roughy fishes would be a tertiary consumer in a food web.