4. What is the central role of helper 'T cells?
(A) Helper T cells are the only immune cell type that can produce immunologicalmemory
(B) Activated helper T cells release perforin that make pores in the target cell'smembrane and enzymes promoting apoptosis leading to cell death
(C) Helper T cells can be activated through innate immune response by antigen-presenting cells such as macrophages and dendritic cells, setting stage for the adaptiveimmune response
(D) Activated helper T cells-Lan produce antibodies