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 59-year-old female presents with gingival condition punched out crater-like depression covered with membrane which can be pulled off painlessly? 
Select and explain. 
A. Diphtheritic lesion, B. Acute herpetic gingivostomatitis, C. ANUG, D. Syphilitic lesion
C: ANUG
Answer: C: ANUG 
Explanation: None