This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Small & Large Intestine, Subject name: Surgery
[{'content': '"Adenoma - carcinoma sequence" is seen in \nSelect and explain. \nA. Follicular thyroid carcinoma, B. Carcinoma gall bladder, C. Carcinoma stomach, D. Carcinoma colon', 'role': 'user'}, {'content': 'Answer: D \nExplanation: (Carcinoma colon) (1177-LB) (1179-B &L 25th)Adenocarcinoma of the colon: microscopically the neoplasm is a columnar cell carcinoma originating in the colonic epithelium. Macroscopically, the tumour may take one of four forms. Type 4 is the least malignant form* It is likely that all carcinomas start as benign adenoma the so called "adenoma-carcinoma sequence"* The annular variety tends to give rise to obstructive symptoms whereas the others more commonly willpresent with bleeding.* Tumours are more common in the left colon and rectum.', 'role': 'assistant'}]