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: Dental
[{'content': 'Temporary hardness of water is due to the presence of following salts of calcium and magnesium: \nSelect and explain. \nA. Bicarbonates, B. Sulphates, C. Chlorides, D. Nitrates', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]