This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Eczema and related disorders, Subject name: Dental
[{'content': 'Patch test is read after: \nSelect and explain. \nA. 2 hrs, B. 2 days, C. 2 wks, D. 2 months', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Patches are commonly applied on upper back for 48 hrs. Patch test First reading is taken after 48 hrs i.e at 2 days 2nd reading on day 4 i.e 96 hrs Evaluation of patch test reading: Grading Evaluation Clinical findings +- Doubt reaction Faint erythema + Weak (non-vesicular) +ve reaction Erythema, infiltration, and discrete papules ++ Strong (vesicular) +ve reaction Erythema, infiltration, papules, and vesicles. +++ Extreme (bullous) + ve reaction Intense erythema, infiltration, and coalescing vesicles.', 'role': 'assistant'}]