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
Tumour marker for Endodermal Sinus Tumour 
Select and explain. 
A. CEA, B. HCG, C. Alfa feto protein, D. Cytokeratin
C: Alfa feto protein
Answer: C: Alfa feto protein 
Explanation: Endodermal sinus tumor (yolk sac tumor) is positive for AFP and α1 - antitrypsin.