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': 'Which of the following iatrogenic condition shown in the given IOPA: \nSelect and explain. \nA. Ledge., B. Perforation., C. Transportation., D. Zipping.', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]