The urine of a man is very dilute,the quantity of urine is excessive,dehydration has started in his body,and he is very thirsty. This condition is caused by:

When $GFR$ (Glomerular Filtration Rate) $.....P......$,the $JG$ (Juxtaglomerular) cells release $.....Q.....$ hormone.
$P\quad\quad Q$

Select the correct option with respect to the following statements:
$(a)$ Angiotensin $II$ constricts arterioles in the kidney to reduce blood flow and decreases blood pressure when blood flow to the afferent arteriole decreases.
$(b)$ Angiotensin $II$ stimulates the adrenal cortex to release aldosterone for more absorption of $Na^+$ and $Cl^-$ ions in the $DCT$.
$(c)$ Blood osmolarity varies with the secretion of aldosterone and $ANP$.

Macula densa refers to . . . . . . .

$RAAS$ is a regulatory mechanism for osmoregulation. It includes . . . . . . group of hormones.

Given below are two statements.
$Statement-I$: Only $ADH$ is sufficient for homeostasis.
$Statement-II$: $RAAS$ stimulates $Na^+$ reabsorption, thereby maintaining the osmolarity of body fluid.
In the light of the above two statements, choose the most appropriate answer from the options given below.