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: Microbiology
The distinguishing characteristic of a positive delayed-type hypersensitivity skin test is 
Select and explain. 
A. Erythema, B. Necrosis, C. Induration, D. Vasculitis
C: Induration
Answer: C: Induration 
Explanation: None