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 complete denture patient presents with angular cheilitis. A review of recent medical examination revealed that vitamin deﬁciency is not a factor. A possible  predisposing factor is: \nSelect and explain. \nA. Excessive vertical dimension of occlusion, B. A closed or insuﬃcient vertical dimension of occlusion, C. Improper balance of the occlusion, D. Poor contour of the denture base', 'role': 'user'}, {'content': 'Answer: B \nExplanation: A closed or insufficient vertical dimension of occlusion is thought to be the one predisposing condition for angular cheilitis, which usually is associated with Candida albicans.\nImproperly balanced occlusion or poor contour of the denture base are not predisposing conditions for angular cheilitis.', 'role': 'assistant'}]