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: Pathology
[{'content': 'The oral mucosa becomes rigid, blanched and opaque in which of the following conditions? \nSelect and explain. \nA. Pemphigus vulgaris, B. Lupus erythematoses, C. Ehlers-Danlos syndrome, D. Submucous fibrosis', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]