During the Algal Blooms Called Red Tides, Consumption of Bivalves

During the algal blooms called red tides, consumption of bivalves is discouraged and harvesting may be prohibited; what aspect of bivalve life history is responsible for this association?

A) Bivalves live along coastlines and are exposed to the same pollutants that cause red tides.
B) Red tides reduce the populations of bivalves below critical the quantities needed by their natural predators.
C) Bivalves filter algae and detritus from the water, causing them to concentrate the algal toxins.
D) Bivalves are the natural bioremediators for red tides; harvesting them prolongs the bloom.