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: Anatomy
[{'content': 'Attachment to the first rib is all except - \nSelect and explain. \nA. Scalenus anterior, B. Scalenus posterior, C. Scalenus medius, D. Suprapleural membrane', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Scalenus posterior is attached to the second rib.', 'role': 'assistant'}]