Killer cells & helper cells are pa of -: (A) B cells, (B) T cells, (C) Monocytes, (D) Macrophages
Answer is B. The category of effector T cell is a broad one that includes various T cell types that actively respond to a stimulus, such as co-stimulation. This includes helper, killer, regulatory, and potentially other T cell types. Reff: Ananthanarayanan & Panikers textbook of microbiology 9th edition pg: 135