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: Pediatrics
20 years old Rajesh presence with fever and chronic cough ESR 35 mm sputum cytology is negative for AFB and tuberculin test show indurations of 19 X 23 mm. The probable diagnosis is - 
Select and explain. 
A. Fungal pneumonia, B. Viral pneumonia, C. Pulmonary T.B., D. Bacterial pneumonia
C: Pulmonary T.B.
Answer: C: Pulmonary T.B. 
Explanation: Ans. is 'c' i.e., Pulmonary T.B. o The history and tuberculin test strongly suggests the diagnosis of T.B. o Do not get confused by negative sputum cytology because negative sputum cytology does not rule out pulmonary tuberculosis. " Sputum cytology is just a presumptive diagnosis" - Harrison " The definitive diagnostic of T.B. depends upon the culture of bacteria obtained from respiratory specimen" - Harrison o The presence of induration > 15 mm in size strongly indicates T.B. infection.