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: Pathology
Which is not a tumour marker - 
Select and explain. 
A. Carcinoembryonic antigen (CEA), B. Human Chorionic Gonadotropin (hCG), C. β2Microglobulin, D. α Fetoprotein (AFP)
C: β2Microglobulin
Answer: C: β2Microglobulin 
Explanation: Note : β2 microglobulin (Monoclonal immunoglobulin) is used in multiple myeloma.