This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
Immunity against cancer cells - 
Select and explain. 
A. Basophills, B. Eosinophils, C. NK cells, D. Neutrophils
C: NK cells
Answer: C: NK cells 
Explanation: Ans. is 'c' i.e., NK cells o NK cells are endowed with an innate ability to kill a variety of tumor cells, virally infected cells, and some normal cells, without previous sensitization. o These cells are pa of the innate immune system, and they may be the first line of defense against viral infections and, perhaps, some tumors.