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': 'Graft versus Host reaction is caused by - \nSelect and explain. \nA. B-Lymphocytes, B. T-Lymphocytes, C. Macrophages, D. Complement', 'role': 'user'}, {'content': "Answer: B \nExplanation: The graft mounts an immune response against the antigens of the host is called graft-versus-host reaction. The immunocompetent T cells of the graft are responsible for this reaction. The recipient possesses transplantation antigens that are absent in the graft. Reference:athanarayan & paniker's 9th edition, pg no: 186 <\\p>", 'role': 'assistant'}]