This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: miscellaneous, Subject name: Pathology
The immune cells with CD16 and CD56 on their surface, which are impoant in immunological surveillance and natural defense against virus infected and malignant cells are- 
Select and explain. 
A. Helper T-cells, B. Dendritic cells, C. Natural killer cells, D. Macrophages
C: Natural killer cells
Answer: C: Natural killer cells 
Explanation: NATURAL KILLER (NK) CELLS. These lymphocytes do not have B or T cell markers, nor are these cells dependent upon thymus for development unlike CD4+ and CD8+ T cells. NK cells carry surface molecules of CD2, CD16, and CD56, but negative for T cell marker CD3. NK cells are morphologically distinct from B and T cells in being large granular lymphocytes. NK cells are pa of the natural or innate immunity. These cells recognize antibody-coated target cells and bring about the killing of the target directly; this process is termed as antibody- dependent cell-mediated cytotoxicity (ADCC). This mechanism is paicularly operative against viruses and tumour cells. Ref: TEXTBOOK OF PATHOLOGY 6th EDITION - HARSH MOHAN PAGE NO:64