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': 'The commonest variation in the aeries arising from the arch of aoa is: \nSelect and explain. \nA. Absence of brachiocephalic trunk, B. Left veebral aery arising from the arch, C. Left common carotid aery arising from brachio cephalic trunk, D. Presence of retroesophageal subclan aery', 'role': 'user'}, {'content': 'Answer: C \nExplanation: C i.e. Left common carotid aery arising from brachiocephalic trunk', 'role': 'assistant'}]