The correct option is C Blue green algae
Blue-green algae (BGA) are Cyanobacteria. The toxins produced by Cyanobacteria are called cyanotoxins. Hydroxylamine is an inorganic cyanotoxin secreted by the BGA. This compound is highly toxic to aquatic life. When the bacteria form aquatic blooms they release a lot of cyanotoxins killing aquatic life on a large scale. When these cyanotoxins enter the shells of molluscans they lead to shellfish poisoning. Thus the correct answer is option C.