The correct option is B It can kill harmful bacteria
Bacillus thuringiensis is a bacterium that produces a toxin, which when ingested by cotton bollworm brings about their death. Hence it can be used as an environment-friendly pesticide. However, it has no action on bacteria or fungi which are harmful to plants. Its spores can be sprayed on crop plants. Bt-Cotton is cotton that has been genetically engineered for containing the gene coding for the toxin of Bacillus thuringiensis.