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
Predisposing clinical condition for endodontic flare up? 
Select and explain. 
A. Acute periapical abscess, B. Acute apical periodontitis, C. Asymptomatic necrotic pulp with periapical lesion, D. Pain and swelling since the treatment
C: Asymptomatic necrotic pulp with periapical lesion
Answer: C: Asymptomatic necrotic pulp with periapical lesion 
Explanation: None