Correct Option (c)
Oysters are bivalve molluscs that are classic examples of filter feeders. They draw water into their mantle cavity through ciliary action on their gills. Microscopic food particles, such as phytoplankton and zooplankton, are trapped in mucus on the gills and subsequently transported to the mouth for ingestion. This feeding mechanism also contributes to the clarification of water in their aquatic habitats.
Incorrect Options
Catfish are primarily benthic scavengers or predators, feeding on detritus, smaller fish, or invertebrates. While some juvenile stages may exhibit limited filter feeding, it is not their primary mode of nutrition as adults.
Octopus is a highly active marine predator. It uses its arms and suckers to capture prey, which it then consumes using a chitinous beak.
Pelicans are piscivorous birds that hunt fish. They employ a gular pouch to scoop fish from the water, a method distinct from filter feeding.