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
The tumor marker that is elevated most frequently in carcinoma of the gall bladder is 
Select and explain. 
A. Alfa fetoprotein (AFP), B. CA 125, C. CA 19 aEUR" 9, D. Carcino-Embryonic Antigen (CEA)
C: CA 19 aEUR" 9
Answer: C: CA 19 aEUR" 9 
Explanation: . CA 19 aEUR" 9