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: Ophthalmology
[{'content': 'Primary action of superior oblique is- \nSelect and explain. \nA. Intorsion, B. Depression, C. Adduction, D. Abduction', 'role': 'user'}, {'content': 'Answer: A \nExplanation: There are six extraocular muscles in each eye.', 'role': 'assistant'}]