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': 'Screening of prostate Ca commonly done bya) DRE (digital rectal exam)b) USGc) MRId) PSAe) CT scan \nSelect and explain. \nA. b, B. ad, C. ac, D. ab', 'role': 'user'}, {'content': 'Answer: B \nExplanation: CSDT 11/e writes - "Even so, the realities of clinical practice are that the combination of digital rectal examination and serum PSA monitoring is the most effective screening protocol."\nThis view of CSDT is supported by Smith\'s Urology\nBut if we have to choose one investigation, it would be PSA.', 'role': 'assistant'}]