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
Specific marker for prostatic cancer is 
Select and explain. 
A. Prostate specific antigen, B. LDH, C. Chromogranin, D. CA 19-9
A: Prostate specific antigen
Answer: A: Prostate specific antigen 
Explanation: PSA + DRE is the best method to screen prostate cancer.