The correct answer is C
Cytotoxic cells are lymphocytes that kills or destroy cancerous cells, infected cells especially the one infected with virus, and damaged cells.
Cytotoxic cells does not secret antibodies to fight pathogens but the secret granzyme and perforin to kills infected cells.
They recognised their host cells by using their T cell receptors(TCR).
it enhances antibody production by t cells of the adaptive immune system.
hope i'm right