The correct option is B Biopesticide
When any microorganism is used as pesticide, then it is known as biopesticide. Insects not only eat plants; bacteria also form occasional part of their diet. In response, several types of bacteria have evolved defense mechanisms against insect predation. Bacillus thuringiensis is used as biopesticide. During sporulation, it forms intracellular crystalline bodies that contain an insecticidal protein called the endotoxin. The endotoxin that accumulates in the bacterium is an inactive precursor. After ingestion by the insect, this protoxin is cleaved by proteases which becomes active because of the alkaline conditions in gut. It results in the shorter versions of the protein that display the toxic activity by binding to the inside of the insects mid gut and damaging the surface epithelium by creating pores that cause swelling and lysis. So, that insect is unable to feed and consequently starves to death.