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: Radiology
[{'content': 'Which of the following cranial nerve can be visualised on plain CT scan? \nSelect and explain. \nA. Optic, B. Trigeminal, C. Facial, D. Hypoglossal', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. Optic', 'role': 'assistant'}]