This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Gluteal Region, Subject name: Anatomy
[{'content': 'Muscle passing through lesser sciatic foramen is? \nSelect and explain. \nA. Obturator externus, B. Obturator intemus, C. Pectinus, D. Piriformis', 'role': 'user'}, {'content': 'Answer: B \nExplanation: ANSWER: (B) Obturator internusREF: Grays anatomy 40th ed chapter 40See table of "STRUCTURES PASSING THROUGH GREATER AND LESSER SCIATIC FORAMINA" in Anatomy 2013 Session 2', 'role': 'assistant'}]