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': 'Reduction in flow of saliva is not generally seen in: \nSelect and explain. \nA. Elderly diabetics, B. b)Patient undergoing radiation therapy, C. Patients suffering from parkinsonism, D. Patients on phenothiazine drugs', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]