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
Air–borne contact dermatitis can be diagnosed by – 
Select and explain. 
A. Skin biopsy, B. Patch test, C. Prick test, D. Estimation of serum IgE levels
B: Patch test
Answer: B: Patch test 
Explanation: Patch testing is the only diagnostic test for diagnosis of contact dermatitis.