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: Medicine
[{'content': 'A paient after vomiting several times develops carpopedal spasm. The most approriate treatment would - \nSelect and explain. \nA. Intravenous injection of 20 ml 10% calcium gluconate solution, B. Intravenous infusion of isotonic saline, C. Oral ammonium chloride 2mg four times a day, D. 5% CO2inhalation', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]