This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General pathology, Subject name: Pathology
Which type of immune responses responsible for caseation necrosis in TB?- 
Select and explain. 
A. Cell-mediated immunity, B. Antibody mediated reaction, C. Allergic reaction, D. Immune complexes
A: Cell-mediated immunity
Answer: A: Cell-mediated immunity 
Explanation: Type 4 or delayed hypersensitivity or T cell mediated reaction is an immune response without formation of antibodies but is instead a slow and prolonged response .examples:reaction against mycobacterium infection ,virally infected cell,malignant cells and organ transplantation.Harshmohan textbook of pathology 7th edition