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: Microbiology
Natural killer cell is: 
Select and explain. 
A. MHC restricted, B. Antibody dependent, C. Null cells, D. B-lymphocytes
C: Null cells
Answer: C: Null cells 
Explanation: Ans. c. Null cells