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': 'What is the amount of bleaching powder required to disinfect 455 litre of water if 4, 5, 6 cup shows distinct colouration in Horrock’s apparantus? \nSelect and explain. \nA. 2 g, B. 8 g, C. 6 g, D. 4 g', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]