This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Organ Transplant / Graft, Subject name: Pathology
[{'content': 'Microcytotoxicity is used for: \nSelect and explain. \nA. Tissue typing, B. Drug allergy, C. Infection Susceptibility, D. Substance toxicity', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Tissue typing is the technique in which the tissues of a prospective donor and recipient are tested for compatibility before carrying out transplantation. The two commonly used techniques are:- 1.Mixed leukocyte reaction for MHC II 2.Micro-cytotoxicity assay for MHC I', 'role': 'assistant'}]