Reabsorption of `Na^(+)` is controlled by
(a) Vasopressin or ADH
(b) Aldosterone
(c) Renin
(d) Rennin

Options

A. Vasopressin or ADH
B. Aldosterone
C. Renin
D. Rennin

Answer

To solve the question regarding which hormone controls the reabsorption of sodium ions (Na^+), we can analyze the options provided:

1. **Understanding the Question**: The question is asking about the regulation of sodium ion reabsorption in the kidneys.

2. **Evaluating the Options**:
- **(a) Vasopressin or ADH**: This hormone primarily regulates water reabsorption in the kidneys, not sodium.
- **(b) Aldosterone**: This hormone is known to regulate sodium reabsorption in the kidneys. It acts on the distal convoluted tubule and collecting duct to increase sodium reabsorption and potassium secretion.
- **(c) Renin**: This enzyme is involved in the renin-angiotensin-aldosterone system (RAAS) but does not directly control sodium reabsorption.
- **(d) Rennin**: This is just an alternative spelling of renin and has the same function as option (c).

3. **Conclusion**: The hormone that primarily controls the reabsorption of sodium ions in the kidneys is **aldosterone**.

Therefore, the correct answer is **(b) Aldosterone**.