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
[{'content': 'Air–borne contact dermatitis can be diagnosed by – \nSelect and explain. \nA. Skin biopsy, B. Patch test, C. Prick test, D. Estimation of serum IgE levels', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Patch testing is the only diagnostic test for diagnosis of contact dermatitis.', 'role': 'assistant'}]