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': 'In sanitary or hygienic pontics, the gap between the gingival tissue and pontic should be at least: \nSelect and explain. \nA. 2 mm, B. 3 mm, C. 4 mm, D. 5 mm', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]