This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Kidney, Subject name: Medicine
[{'content': 'Common age of presentation of Henoch schnolein purpura- \nSelect and explain. \nA. < 10 years, B. 10-15 years, C. 15-20 years, D. 20-30 years', 'role': 'user'}, {'content': 'Answer: A \nExplanation: IgA vasculitis is most often seen in children. Most patients range in age from 4to7 years . Disease may also be seen in infants and adults. Male to female ratio is 1.5:1 A seasonal variation with a peak incidence in spring has been noted Ref Harrison 20th edition pg no 2586', 'role': 'assistant'}]