This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology, Subject name: Microbiology
[{'content': 'A single immunoglobulin molecule contains - \nSelect and explain. \nA. 1 light chain, 1 heavy c hain, B. 2 heavy chains, 1 light, C. 2 light chains, 2 heavy chains, D. 2 light chains, 1 heavy chain', 'role': 'user'}, {'content': "Answer: C \nExplanation: They are typically made of basic structural units--each with two large heavy chains and two small light chains. Ref: Ananthanarayan & Parker's textbook of microbiology 9th edition pg: 94", 'role': 'assistant'}]