This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Orbit, Subject name: Ophthalmology
[{'content': 'Blow out fracture affects which orbital wall ? \nSelect and explain. \nA. Lateral wall, B. Posteromedial part of orbital floor, C. Superior wall, D. Anterosuperior roof', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Posteromedial part of orbital floor * 'The orbital floor overlies the maxillary sinus without reinforcement, therefore is weaker and more blowouts tend to occur here especially in the posteromedial floor'", 'role': 'assistant'}]