The correct option is D All of the above
The functioning of the kidneys is efficiently monitored and regulated by hormonal feedback mechanisms involving the hypothalamus, JGA and heart.
Hypothalamus - when there is an excessive loss of fluid from the body they triggere the osmoreceptors to stimulate the hypothalamus to release antidiuretic hormone (ADH). ADH facilitates water reabsorption from latter parts of the tubule, thereby preventing diuresis. Thus restoring water and blood volume.
When there is a fall in glomerular blood flow/glomerular blood pressure/GFR can activate the JG cells of JGA complex to release renin which converts angiotensinogen in blood to angiotensin I and further to angiotensin II. Angiotensin II, being a powerful vasoconstrictor, increases the glomerular blood pressure and thereby GFR.
When there is a increase in blood pressure, it stimulates the atria of the heart causing the release of Atrial Natriuretic Factor (ANF). ANF can cause vasodilation (dilation of blood vessels) and thereby decreasing the blood pressure.