A 7 year old girl with non productive cough, mild stridor for 3 months duration.Patient is improving but suddenly developed wheeze productive cough mild fever and hyperlucency om CXR and PFT shows obstructive curve.Diagnosis is ?

• A. Pulmonary alveolar microlithiasis
• B. Follicular bronchitis
• C. Bronchiolitis obliterans
• D. Hemosiderosis