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
[{'content': 'Marker for carcinoma colon is: September 2005, March 2013 \nSelect and explain. \nA. AFP, B. CA-125, C. CEA, D. HCG', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. C: CEA', 'role': 'assistant'}]