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: March 2013 (a) \nSelect and explain. \nA. Adduction, B. Intorsion, C. Abduction, D. Extorsion', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. B i.e. Intorsion Extraocular muscles Intoors of the eye: Superior oblique & Superior rectus Action of superior oblique: Abduction, Inoion & Depression Nerve supply of superior oblique: Trochlear (4th cranial nerve) Levator palpebrae superioris is supplied by: 3rd cranial nerve (oculomotor) Muscle attached to posterior tarsal margin: Muller's muscle", 'role': 'assistant'}]