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: Surgery
[{'content': 'A 23 years old female patient complains of decreased mouth opening since 4 days. This could be due to: \nSelect and explain. \nA. Impacted third molar, B. Oral submucous fibrosis, C. Oropharyngeal fibrosis, D. Bony ankylosis of TMJ', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]