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: Pharmacology
[{'content': 'Most unpleasant side effect of salbutamol is: \nSelect and explain. \nA. Tremors, B. Hypertension, C. Rhinorrhoea, D. Headache', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]