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
Components of Innate immunity that are active against viral cells includes - 
Select and explain. 
A. NK cells, B. Cytotoxic cells, C. B-cell, D. Memory B cell
A: NK cells
Answer: A: NK cells 
Explanation: A class of lymphocytes called natural killer cells or NK cells are impoant in nonspecific defense against viral infections and tumors. They selectively kill virus-infected cells and tumors cells. - they are activated by interferons. Reference : Anathanarayan & paniker's 9th edition, pg no:81 <\p>