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
A common type of Ca in middle 3rd of the esophagus- 
Select and explain. 
A. Adeno Carcinoma, B. Squamous Carcinoma, C. Adeno squamous Carcinoma, D. Leiomyosarcoma
B: Squamous Carcinoma
Answer: B: Squamous Carcinoma 
Explanation: Esophageal carcinoma is of two common histological types -
1. Squamous cell carcinoma

Most common type worldwide.
Most common type in India.
Occurs in upper and middle 1/3rd of esophagus.

2. Adenocarcinoma

Most common type in the USA.
Located in the lower 1/3rd of esophagus.