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: Dental
A 40 year old male complained of pain and mobility of tooth, associated with swelling and pus discharge from gingiva. What is the diagnosis? 
Select and explain. 
A. Periapical granuloma, B. Periodontal abscess, C. Periodontal cyst, D. Periapical cyst
B: Periodontal abscess
Answer: B: Periodontal abscess 
Explanation: Radiograph reveals periapical radiolucency associated with bone loss suggestive of periodontal abscess.