There are many different categories of t-cells that carry out various roles for the immune system. differentiation for most t-cells occurs during the t-cell maturation, but some differentiation occurs after maturation following antigen presentation. one category of t-cells functions in antigen presentation and activation of b cells, as well as the activation of cytotoxic t-cells and macrophages. what is this category of t-cell? a) t b) memory t c) regulatory t d) natural killer t