This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Oncology, Subject name: Medicine
[{'content': 'A 69-year-old man has lost a friend to prostate cancer, and would like to be evaluated for the disease. He has no urinary symptoms. Which of the following tests is most likely indicated to screen him for prostate cancer? \nSelect and explain. \nA. prostate ultrasound, B. digital rectal examination (DRE), C. DRE and prostate specific antigen (PSA), D. PSA', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Although an elevated PSA (> 4) has the best positive predictive value, combining it with DRE is probably the most effective screening process.', 'role': 'assistant'}]