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': 'If during rubber dam application, you see the gingiva is protruding out of margins; what can be the cause for it? \nSelect and explain. \nA. Holes on rubber dam placed too far from each other, B. Holes on rubber dam placed too close from each other, C. Gingival tissue around holes are oedematous, D. Rubber dam is too thin', 'role': 'user'}, {'content': "Answer: B \nExplanation: Holes punched too close together - holes pull away from teeth causing leakage.\nHoles punched too far apart- dam bunches up between teeth.\nHoles position too low on the dam - dam covers patient's eyes or nose.\nHoles position too high on dam - dam does not extend over upper lip.", 'role': 'assistant'}]