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
Direct immunofluorescence is positive in – 
Select and explain. 
A. Atopic dermatitis, B. SLE, C. Pemphigus, D. Secondary syphilis
C: Pemphigus
Answer: C: Pemphigus 
Explanation: None