Ans. is 'd' i.e., Antrax Bioterrorismo A bioterrorism attack is the delibrate release of viruses, bacteria or other germs (agents) used to cause illness or death in people, animals or plants. These agents are typically found in nature, but it is possible that they could be changed to increase their ability to cause disease, make them resistant to current medicines or to increase their ability to be spread into the environment. Biological agents can be spread through the air, through water or in food. Terrorists may use biological agents because they can be extermely difficult to detect and do not cause illness for several hours to several days. Some bioterrorism agents, like the small pox virus, can be spread from person to person and some like anthrax, cannot.Bioterrorism agent categoriesCategory Ao These high priority' agents include organisms or toxins that pose the highest risk to the public and national security because:They can be easily spread or transmitted from person to person.They result in high death rates and have potential for major public health impact.They might cause public panic and social disruption.They require special action for public health preparedness.Category Bo These agents are second highest priority because:i) They are moderately easy to spread,ii) They result in moderate illness rates and low death rates.iii) They require specific enhancements of CDC's laboratory capacity and enhanced disease monitoring.Category Co These third highest priority agents include emerging pathogens that could be engineered for mass spread in the future because:They are easily available.They are easily produced and spread.iii) They have potential for high morbidity and mortality rates and major health impact.CDC Category A, B, and C AgentsCategory AAnthrax (Bacillus ant hr acts)Botulism (Clostridium botulinum toxin)Plague ( Yersinia pest is)Smallpox (Variola major)Tularemia (Francisella tularensis)Viral hemorrhagic feversArenaviruses : Lassa. New World (Machupo, Junin, Guanarito, and Sabia) Bunyaviridae: Crimean Congo. Rift Valley Filoviridae: Ebola. MarburgFlaviviridae : Yellow fever: Omsk fever; Kyasanur ForestCategory BBrucellosis (Brucella spp.)Epsilon toxin of Clostridium perfringensFood safety threats (e.g.. Salmonella spp., Escherichia coli 0157:H7, Shigella) Glanders (Burkholderia mallei)Melioidosis {B. pseudomallei)Psittacosis (Chlamydia psittaci)Q fever (Coxiella burnetii)Ricin toxin from Ricinus communis (castor beans)Staphylococcal enterotoxin BTyphus fever {Rickettsia prowazekii)Viral encephalitis Water safety threats (e.g. Vibrio cholerae, Cryptosporidium parvum)Category CEmerging infectious diseases threats such as Nipah, hantavirus, and SARS coronoavirus.