Scientists grouped fish into

Fish are broadly classified into two main categories:  1. Finfish (e.g., salmon, tuna) - Characterized by bony skeletons and fins  2. Shellfish - Further divided into:  a. Crustaceans (e.g., shrimp, crabs)  b. Mollusks (e.g., clams, oysters) The other options are incorrect because:  • (A) & (D): There are no scientifically recognized 4 or 5 primary fish groups  • (B): While shellfish can be subdivided, the highest classification level recognizes only two main types Key Point: This binary classification is universally accepted in food science and marine biology, with all fish species falling under one of these two umbrella categories. The distinction is particularly important in food safety standards, as shellfish often require different handling protocols due to higher allergen risks.