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': 'Ca(OH)2 is given \nSelect and explain. \nA. In weeping canal, B. When there is bleeding from root canals, C. As a sterilizing agent, D. To remove or dissolve Periapical debris', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]