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: Surgery
[{'content': 'Which of the following is the investigation of choice for assessment of depth of penetration and perirectal nodes in rectal cancer - \nSelect and explain. \nA. Trans rectal ultrasound, B. CT Scan pelvis, C. MRI Scan, D. Double contrast Barium enema', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is 'c' i.e., M.R.I. Scan", 'role': 'assistant'}]