This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Pathology
[{'content': 'Parietal cells in the stomach secrete a protein crucial for the absorp on of vitamin B12 by the ileum. What is this protein? \nSelect and explain. \nA. Intrinsic factor, B. Gastrin, C. Somatostatin, D. Cholecystokinin (CCK)', 'role': 'user'}, {'content': 'Answer: A \nExplanation: .', 'role': 'assistant'}]