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': 'Which structure can be felt at the lower pa of the medial border of sternocleidomastoid: \nSelect and explain. \nA. Subclan aery, B. Common carotid aery, C. Internal mammary aery, D. Maxillary aery', 'role': 'user'}, {'content': 'Answer: B \nExplanation: B. i.e. Common carotid aery', 'role': 'assistant'}]