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: Pathology
The most common site and type of metaplasia are : 
Select and explain. 
A. Respiratory tract epithelium, Columnar metaplasia, B. Respiratory tract epithelium, Squeamous metaplasia, C. Esophagus, Squeamous metaplasia, D. Esophagus, Columnar metaplasia
B: Respiratory tract epithelium, Squeamous metaplasia
Answer: B: Respiratory tract epithelium, Squeamous metaplasia 
Explanation: As respiratory tract is exposed to chronic irritation due to dust, Smoke etc, it undergoes squeamous metaplasia ,