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': 'Maximum delay allowed to pour cast with Hydrocolloids impression material \nSelect and explain. \nA. 15 min, B. 30 min, C. 45 min, D. 2 hours', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Immediate pouring is required. Maximum 30 min can be there, stored at 100% relative humidity in 2% K2SO4 solution.', 'role': 'assistant'}]