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
Flourescence test is positive for all except: 
Select and explain. 
A. Pemphigus., B. Erythema multiformae., C. Scleroderma., D. Bullous pemphigoid.
C: Scleroderma.
Answer: C: Scleroderma. 
Explanation: None