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': 'Which protein is absent in saliva? \nSelect and explain. \nA. Lactoferrin, B. Amylase, C. Mucin, D. Intrinsic factor', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Intrinsic factor is secreted by the parietal cells of the stomach and is not secreted by the salivary glands. Lactoferrin, amylase, mucin, and muramidase are found in saliva.', 'role': 'assistant'}]