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: Anaesthesia
[{'content': 'Intra aireal injection of thiopentone causes: \nSelect and explain. \nA. Vasospasm, B. Vasodialation, C. Necrosis of vessel wall, D. Hypotension', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A i.e. Vasospasm', 'role': 'assistant'}]