Answer:
d. Preload increases.
Explanation:
Preload is affected by the rate of venous return and the venous blood pressure , which are affected by the volume of circulating blood and venous tone .
The preload is related to ventricular end - diastolic volume ,
The higher end - diastolic volume have a higher preload .
Preload is approximated via  echocardiographic measurement end diastolic volume or EDV.
Preload is increased by exercising , or increase in blood pressure and neuroendocrine excitement .
