A patient is admitted to the hospital with a CD4 spinal cord injury after a motorcycle collision. The patient's BP is 83/49, and his pulse is 39 beats/min, and he remains orally intubated. The nurse identifies this pathophysiologic response as caused by
a. increased vasomotor tone after injury
b. a temporary loss of sensation and flaccid paralysis below the level of injury
c. loss of parasympathetic nervous system innervation resulting in vasoconstriction
d. loss of sympathetic nervous system innervation resulting in peripheral vasodilation