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': 'A 29 year old male patient complains of protruding upper incisors. The incisor relationship can be classified as Class II div 1. This system of classification for incisor relationship was described by: \nSelect and explain. \nA. E. Angle, B. British Standards Institute, C. Ackerman-Proffit system, D. Dewey', 'role': 'user'}, {'content': 'Answer: B \nExplanation: British Standard Classification of Incisor Malocclusion:\n\nClass I: The lower incisor edges occluded on or lie below the cingulum plateau of the upper incisors.\xa0\nClass II, division 1: The lower incisor edges\xa0occluded behind the cingulum plateau of the upper incisors and the upper incisors are normally inclined or proclined.\xa0\nClass II, division 2: The lower incisor edges occluded behind the cingulum plateau of the upper incisors and the upper incisors are retroclined.\xa0\nClass III: The lower incisor edges occlude anterior to the cingulum plateau of the upper incisors.\n\nRef: British Standards Institute. Glossary of Dental Terms (BS 4492). London: BSI; 1983.', 'role': 'assistant'}]