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
In a 19 years old patient, with a swelling over the left angle of the mandible, temperature of 38°C and negative history of trauma, one should suspect: 
Select and explain. 
A. Spontaneous fracture of the mandible, B. Pericoronal infection, C. Mumps, D. Sjogren's syndrome
B: Pericoronal infection
Answer: B: Pericoronal infection 
Explanation: None