This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Oncology, Subject name: Medicine
[{'content': 'Specific Tumor marker is seen in - \nSelect and explain. \nA. Ca breast, B. Ca lung, C. Ca liver, D. Ca ovary', 'role': 'user'}, {'content': 'Answer: A \nExplanation: <img src=" /> Ref Harrison 20th edition pg 528', 'role': 'assistant'}]