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
A 71/2 months old child with cough, mild stridor was staed on oral antibiotics. The child showed initial improvement but later developed wheeze, productive cough, and mild fever. X-ray shows hyperlucency and PFT shows an obstructive curve. The most probable diagnosis is: 
Select and explain. 
A. Bronchiolitis obliterans, B. Post viral syndrome, C. Follicular bronchitis, D. Pulmonary alveolar microlithiasis
A: Bronchiolitis obliterans
Answer: A: Bronchiolitis obliterans 
Explanation: The patient in question is presenting with charachteristic features of bronchiolitis obliterans. Fever, cough, and wheeze are common clinical features of bronchiolitis obliterans and a period of initial improvement may well be seen in cases of bronchiolitis obliterans (Initial sign of B.O). Hyperluscency or chest X-Ray and obstructive curve on pulmonary function tests fuhur suggest the diagnosis of bronchiolitis obliterans. Ref: Nelson 18th Edition, Page 1782