A 22-year-old man enters the hospital emergency room after severing a major artery in a motorcycle accident. It is estimated that he has lost approximately 700 ml of blood. His blood pressure is 90/55 mm Hg. Which of the following sets of changes would be expected in response to hemorrhage in this man?
A、Heart rate↑, Sympathetic nerve activity↑, Total peripheral resistance↑.
B、Heart rate↓, Sympathetic nerve activity↑, Total peripheral resistance↑.
C、Heart rate↑, Sympathetic nerve activity↑, Total peripheral resistance↓.
D、Heart rate↓, Sympathetic nerve activity↓, Total peripheral resistance↓.