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
[{'content': 'Most common site for squamous cell carcinoma esophagus is: \nSelect and explain. \nA. Upper third, B. Middle third, C. Lower third, D. Gastro-esophageal junction', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Answer is B (Middle 1/3rd) The most common site of squamous cell carcinoma of esophagus is middle 1/3rd. Site of squamous cell carcinoma Percentage of total Upper 1/3rd 20% Middle 1/3rd 50% Lower 1/3rd 30%', 'role': 'assistant'}]