This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Head and neck blood supply and scalp, Subject name: Anatomy
[{'content': 'Exposure of left subclan aery by supraclavicular approach does NOT require cutting of: \nSelect and explain. \nA. Sternocleidomastoid, B. Scalenus anterior, C. Scalenus medius, D. Omohyoid', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Scalenus medius muscle lies postero-inferior to subclan aery and is not required to be cut.', 'role': 'assistant'}]