The non-specific response, also called innate immunity, is a generalized response to infections that involve white blood cells and plasma proteins. Is called innate because it does not involve immunologic memory.
One of the mechanisms used in innate immunity is phagocytosis, where the cells surround and engulf the pathogen or foreign substance to isolate them and destroy them.
Some of the cells that are part of the innate immune system are the neutrophils, macrophages or monocytes, dendritic cells, and natural killer cells (NK cells).
Natural killer cells detect cells infected by viruses or abnormal cells that can become cancerous in a very fast way, and cause the death of the affected cell by lysis or apoptosis.
This means A) Natural Killer cells (NK cells) is the right answer.