Tina is a hard-working sales clerk in a busy department store. She has stood completely still behind the check-out counter for an 8-hour shift. At the end of Tina's shift she finds that she feels somewhat dizzy and guesses that her blood pressure is quite low. All of the following factors normally contribute to homeostatic blood pressure regulation. Which one is most likely contributing to her symptoms? a. All of these
b. Decreased skeletal muscle pump
c. Increased activity of the pulmonary pump
d. Defective baroreceptor detection in the carotid artery
e. Increased sympathetic tone