This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Pathology
[{'content': 'M.C. site of Ca esophagus is \nSelect and explain. \nA. Middle 1/3 rd, B. Upper 1/3 rd, C. Lower 1/3rd, D. Lower end of esophagus', 'role': 'user'}, {'content': 'Answer: C \nExplanation: tumors of oesophagus usually occurs in distal third of oesophagus and may invade gastric cardia ROBBINS TEXT BOOK OF PATHOLOGY 9TH EDITION PD NO.662', 'role': 'assistant'}]