This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Social & Preventive Medicine
[{'content': 'Which of the following do not cause hardness of water ? \nSelect and explain. \nA. Calcium carbonate, B. Calcium sulphate, C. Calcium bicarbonate, D. Magnesium bicarbonate', 'role': 'user'}, {'content': 'Answer: A \nExplanation: * Temporary hardness is a type of water hardness caused by the presence of dissolved bicarbonate minerals (calcium bicarbonate and magnesium bicarbonate). * Permanent hardness is caused by dissolved calcium sulfate (which is not removed by boiling ref : park 21st ed', 'role': 'assistant'}]