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: Medicine
A 45 year old, HIV positive patient presents with features of pneumonia. Characteristic histopathological features suggesting pneumocystis carinii pneumonia is: 
Select and explain. 
A. Prominent Interstitial Pneumonitis, B. Eosinophilic Alveolar Exudates, C. Prominent mononuclear cells in Alveolar exudates, D. Neutrophilic infiltration of alveolar interstitium
B: Eosinophilic Alveolar Exudates
Answer: B: Eosinophilic Alveolar Exudates 
Explanation: Answer is B (Eosinophilic Alveolar Exudate): The most characteristic histoputhological feature of pneumocystis carinii pneumonia in adults is predominantly alveolar, foamy vacuoloted, eosinophilic exudates. Interstitial pneumonitis is usually mild and shows infiltration with PML and mononuclear cells.