This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology, Subject name: Microbiology
Helper cells belong to? 
Select and explain. 
A. T cells, B. Macrophages, C. B cells, D. Monocytes
A: T cells
Answer: A: T cells 
Explanation: 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