A 59-year-old black man has a rock-hard, discrete, 1.5-cm nodule that is felt in his prostate during a routine physical examination. He is completely asymptomatic, and his
prostatic specific antigen (PSA) done 3 months ago was normal for his age. His last rectal examination was performed a year earlier and was unremarkable. Which of the following will best establish the diagnosis? A. ...