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': 'Which cells cause rosette formation with sheep RBCs? \nSelect and explain. \nA. T cells, B. NK cells, C. Monocytes, D. B cells', 'role': 'user'}, {'content': 'Answer: A \nExplanation: 1. Both T-cell and B-cell form rosette with sheep erythrocytes. But best answer is T-cells because T-cells directly react with sheep erythrocytes, whereas B-cells react with sheep erythrocytes that are coated with antibody and complement. 2. Most human T cells have receptors for sheep erythrocytes on their surface and have the ability to form rosettes with them; this propey is made use of for identifying T cells in a mixed population of cells', 'role': 'assistant'}]