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': 'All of the following are aerial supply of sternocileidomastoid muscle, except: \nSelect and explain. \nA. Posterior auricular aery, B. Occipital aery, C. Thyrocervical trunk, D. Superior thyroid aery', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Posterior auricular aery', 'role': 'assistant'}]