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': 'The main disadvantage of using wing shaped rubber dam retainer is: \nSelect and explain. \nA. It does not provide extra retention of the rubber dam, B. Laceration to the gingival tissue, C. Interferes with placement of matrix band, D. None of the above', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]