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': 'Ca colon, investigation of choice is - \nSelect and explain. \nA. CT scan, B. Ba enema, C. Colonoscopy, D. X-ray abdomen', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is 'c' i.e., Colonoscopy * Colonoscopy with biopsy of suspect lesions is the gold standard test for establishing the diagnosis of CA colon.", 'role': 'assistant'}]