[A] : The hormone aldosterone is secreted by adrenal cortex after the low `Na^+` content in blood and the resultant low BP causes the kidney to release renin.
[R]: Renin in blood leads to the formation of angiotensin II which causes adrenel cortex to release aldosterone that causes kidney to re- tain `Na^+` and, therefore, water is reabsorbed and BP rises.

Options

A. If both A and R are true and R is the correct explanation of A
B. If both A and R are true but R is not the correct explanation of A
C. If A is true and R is false
D. If both A and R are false

Answer

A