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
A-34 year old person has rapidly developing cough, dyspnoea, expectoration and blood tinged sputum. He is febrile cyanosed and toxic.Chest examination reveals crepitation and rhonchi. The most likely diagnosis is - 
Select and explain. 
A. Legionella pneumonia, B. Pneumonic plague, C. Septicaemic plague, D. Pulmonary tuberculosis
B: Pneumonic plague
Answer: B: Pneumonic plague 
Explanation: Ans. is 'b' i.e., Pneumonic plague . Radidly developing cough, dyspnea, blood tinged sputum with fever and cyanosis is the classical presentation of pneumonic plague. About other options Option 'a' . Legionnaires pneumonia presents as mild cough, only slight production of cough . There is associated diarrhea and neurological abnormalities. . There is no cyanosis Option 'c' Usually in septicemic plague respiratory symptoms do not occur. Option 'd' . Tuberculosis has gradual course.