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
Killer cells & helper cells are part of - 
Select and explain. 
A. B cells, B. T cells, C. Monocytes, D. Macrophage
B: T cells
Answer: B: T cells 
Explanation: Option b is partially correct :
Helper cells are CD-4 T cells
Killer cells are antibody dependent cytotoxic cells, which belong to large granular lymphocytes (not T cells).