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
A 23 years old female patient complains of decreased mouth opening since 4 days. This could be due to: 
Select and explain. 
A. Impacted third molar, B. Oral submucous fibrosis, C. Oropharyngeal fibrosis, D. Bony ankylosis of TMJ
A: Impacted third molar
Answer: A: Impacted third molar 
Explanation: None