This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
Which amongst the following biological agents has the highest potential for use as a biological weapon for microbial bioterrorism - 
Select and explain. 
A. Plague (Yersinia pestis), B. Small pox (variola major), C. Botulism (Cl. botulinum), D. Brucellosis (Brucella sp)
A: Plague (Yersinia pestis)
Answer: A: Plague (Yersinia pestis) 
Explanation: Plague, smallpox and Botulinum all belong to category 'A' agents of microbial bioterrorism as classified by U.S. Centre for Disease Control and Prevention (CDC). All these agents represent 'high' risk to national security and represent potentially dangerous agents as biological weapons.
‘The highly contagious nature and high mortality of plague make it a close to an ideal agent of bioterrorism, particularly if delivered in a weaponized form.'