Detailed Explanation:

Answer: Option 3 — Oyster

Oysters are filter feeders that strain suspended matter and food particles from water by passing it over specialized filtering structures called gills. Among the given options, only oysters possess this feeding mechanism, while catfish are bottom feeders, octopuses are predators, and pelicans are visual hunters that catch fish.

📝 Short Notes: Filter Feeders

• Definition: Filter feeders are organisms that feed by straining suspended matter and food particles from water through specialized filtering structures.
• Common Examples: Clams, oysters, mussels, sponges, krill, baleen whales, and certain fish including some sharks.
• Avian Filter Feeders: Flamingos and certain duck species use filter feeding mechanisms.
• Ecological Role: Filter feeders act as ecosystem engineers by clarifying water and removing suspended particles, improving water quality.
• Bioaccumulation: They serve as indicator organisms due to their role in bioaccumulation of pollutants and toxins from water.
• Pearl Production: Oysters and mussels are commercially important for pearl farming, practiced in states like Gujarat, Maharashtra, Kerala, Odisha, and others in India.