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: Microbiology
[{'content': 'A child present with recurrent episodes of sinopulmonary infection by bacteria with polysaccharide rich capsule. Deficiency of which of the following immunoglobulin subclasses should be specifically investigated - \nSelect and explain. \nA. IgA, B. IgG 1, C. IgG2, D. IgA + IgG2', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]