This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Esophagus, Subject name: Surgery
[{'content': 'Squamous cell carcinomas of the esophagus most commonly occur \nSelect and explain. \nA. At the GEJ, B. Middle 1/3rd, C. In the lower thoracic esophagus, D. Evenly distributed throughout the esophagus', 'role': 'user'}, {'content': 'Answer: B \nExplanation: - MC type of CA Esophagus World Wide - Squamous cell carcinoma- MC type of CA in western countries - Adenocarcinoma- MC site of Squamous cell carcinoma - Middle 1/3rd- MC site of Adenocarcinoma - Lower 1/3rd- MC site of CA Esophagus overall - Middle 1/3rd- SCC - more common in low socio-economic status- Adenocarcinoma - more common in high socio-economic status', 'role': 'assistant'}]