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: Social & Preventive Medicine
[{'content': 'Which of the following is not true regarding bleaching powder – \nSelect and explain. \nA. Contact period is one hour, B. Volume of water is estimated, C. Immediatly dissolved in water, D. Chlorine demand is estimated', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]