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
A patient presents with complains of sciatica. On radioligical examination there was sclerotic lesions on his skull. Which of the following is most likely to be elevated in this patient - 
Select and explain. 
A. CEA, B. Prostate specific antigen, C. Alkaline phosphatase, D. Alpha 1 antitrypsin
B: Prostate specific antigen
Answer: B: Prostate specific antigen 
Explanation: None