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
A person experiences throbbing pain at night. It is due to 
Select and explain. 
A. Acute pulpal degeneration, B. Acute periodontal abscess, C. Chronic pulpitis, D. Cellulitis
A: Acute pulpal degeneration
Answer: A: Acute pulpal degeneration 
Explanation: None