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 years old person has rapidly developing cough, dyspnoea, expectoration and blood tinged sputum. He is febrile, cyanosed, and toxic. Chest examination reveals crepitations and ronchi. The mostlikely diagnosis is: 
Select and explain. 
A. Legionella, B. Pneumonic plague, C. Septicemic plague, D. Pulmonary tuberculosis
B: Pneumonic plague
Answer: B: Pneumonic plague 
Explanation: Pneumonic plague