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': 'First branch of subclavian artery is \nSelect and explain. \nA. Internal thoracic artery., B. Thyrocervical trunk., C. Vertebral artery., D. Costocervical trunk.', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]