This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology Pa 1 (Immune Response, Antigen-Antibody Reactions, Hypersensitivity, Structure of Immune System, Immunodeficiency Disorders), Subject name: Microbiology
[{'content': 'A child is suffering from recurrent chronic infections with encapsulated bacteria; Which subclass of IgG does the child has deficiency? \nSelect and explain. \nA. IgG1, B. IgG2, C. IgG3, D. IgG4', 'role': 'user'}, {'content': 'Answer: B \nExplanation: IgG2 and IgA deficiency leads to increased risk of infections with encapsulated bacteria.', 'role': 'assistant'}]