The Answer is E.) All of the above
Natural Killer cells, although from a lymphoid progenitor, play a large role in the innate immune response to virally infected cells and tumor formations. Their role resembles that of Cytotoxic T-Cells (CD8+) in the adaptive response.
Cytokines are crucial for cell signaling (chemical messengers) that help regulate the innate and adaptive immune response.
Mucus plays a role in the innate immune system as a physical barrier. It helps keep inhaled or ingested pathogenic microbes from infiltrating the epithelial layer. It also provides a matrix for M-cells and Dendritic cells to sample antigens from to present to the adaptive immune cells.
Macrophages are innate immune cells referred to as an Antigen Presenting Cells (APC's) that recognize foreign pathogens, phagocytose them, and will destroy the pathogen and present the fragments to T-Helper Cells to initiate an Adaptive Response.