This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
Most Impoant hormone responsible for volume maintenance? 
Select and explain. 
A. Aldosterone, B. Angiotensin, C. ADH, D. Renin
C: ADH
Answer: C: ADH 
Explanation: Ans. is 'c' i.e., ADH[Rel Principles of medical physiology p. 412; Ganong 2,{h/e p. 7041"Despite its effect on Na* and water reabsorption, aldosterone k a weak regulator of boily Na+ and water balance, the majorregulator being the 'thirst-ADH' mechanism, Aldosterone k the sole regulator of external potassium balance'.- Principles of medical physiology