The correct option is B E.coli
Biological weapon or germ weapon, are a number of disease-producing agents such as bacteria, viruses, rickettsiae, fungi, toxins, or other biological agents that may be utilized as weapons against humans, animals or plants. Single-celled bacteria that cause diseases such as anthrax (Bacillus anthracis), botulism (Clostridium botulinum), brucellosis, tularemia, and plague (Yersinia pestis) are used as bioweapons. Escherichia coli is a Gram-negative, bacteria commonly found in the lower intestine of warm-blooded organisms. E.coli bacteria cause food poisoning symptoms such as abdominal cramps and diarrhea. It is not related with bioweapons. Thus, the correct answer is option C.