This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Osteology of Thorax, Subject name: Anatomy
[{'content': 'Attachment to First rib is all EXCEPT \nSelect and explain. \nA. Scalenius-anterior, B. Scalenius posterior, C. Scalenius-medialus, D. Suprapleural membrane', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans is 'b' i.e. Scalenus posterior Scalenus posterior is attached to the outer surface of the 2nd rib*.", 'role': 'assistant'}]