This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Pharynx, Subject name: ENT
The most common cause of parapharyngeal abscess in adults is? 
Select and explain. 
A. TB, B. Tooth extraction, C. Tonsillitis, D. Lymphadenitis
B: Tooth extraction
Answer: B: Tooth extraction 
Explanation: The most common aetiology of parapharyngeal abscess is tonsillitis. The most common aetiology of parapharyngeal abscess in adults is dental caries or tooth extraction. Other causes of parapharyngeal abscess occur as a result of the spread of infection from parotid, retropharyngeal, preveebral and submandibular space. (Ref: Scott Brown, 8th edition, VOL 3 )