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': 'One of the most remarkable aspects of the human immune system is its diversity, that is, the ability to recognize a wide range of antigens and to mount a specific antibody response. This is called clonal selection. At the cellular level, which of the following are primarily responsible for such specificity? \nSelect and explain. \nA. Cytotoxic T cells, B. Hypervariable regions in domains of B cells, C. The major histocompatibility complex, D. Specific T cell receptors', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The great heterogeneity in the B cell response is characterized by a wide variety of antigenic stimuli. The end result of this remarkable process is a set of very specific surface receptors on B lymphocytes. However, it is the hypervariable regions in the variable domain of these B cells that provide the amino acid residues that confer specificity by synthesis of surface immunoglobulin receptors. T cells, on the other hand, do not secrete immunoglobulins.', 'role': 'assistant'}]