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': 'Best investigation for prostate cancer is - \nSelect and explain. \nA. Prostate Specific Antigen, B. Acid Phosphatse, C. PSA velocity, D. Alkaline phosphatase', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Answer- C. PSA velocityFor men with a PSA above 4, PSA velocity of more than .75 ng/ml year is suggestive of Ca.While for those with lower PSA levels, rates above 0.5 ng/ml per year should be used to advise biopsy.', 'role': 'assistant'}]