Planktons are the organisms that float on the surface of water bodies. They may be animal like (Zooplankton) or plant like (Phytoplankton).
Pelagic is the zone of water body. Benthos are bottom dwellers. They live in the bottom of sea or lakes where relatively little light penetrates and pressure is high due to the water column.
Neritic means animals living in muddy or sandy bottoms near the sea shore. Thus, the correct answer is option A.