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: Physiology
[{'content': 'Delusion in delirium are \nSelect and explain. \nA. Transient, B. Frightening, C. Self reference, D. Nihilistic', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Delusion are only for sho time so transient in nature. It is the most characteristic feature of the delision. But they may be frightening in nature. So option A is the best answer.', 'role': 'assistant'}]