Eileen Notices That Her Herpes Infection Is Especially Likely to Flare

Eileen notices that her herpes infection is especially likely to flare up during the stressful occasions when she needs to work overtime hours in order to meet pressing deadlines.This is most likely to be caused by her body's

A) reduced levels of serotonin.
B) increased levels of NK cells.
C) reduced levels of lymphocytes.
D) increased levels of epinephrine.