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: Unknown
[{'content': 'A child scratches his hand with a pen. A red wheal appears which persists for 30 minutes. What would be the diagnosis? \nSelect and explain. \nA. Atopy, B. Contact urticarial, C. Pressure urticarial, D. Dermographism', 'role': 'user'}, {'content': "Answer: D \nExplanation: (Refer: Fitzpatrick's Dermatology in General Medicine, 8th edition, pg no: 414-420)\nVariant forms of physical urticaria", 'role': 'assistant'}]