## Core Concept
The loop of Henle plays a critical role in concentrating or diluting the urine based on the body's needs, with the thick ascending limb (TAL) being a key site for ion reabsorption. The **Na+-K+-2Cl- cotransporter (NKCC2)** is a key transporter in the TAL.

## Why the Correct Answer is Right
The thick ascending loop of Henle reabsorbs approximately **25-30%** of filtered sodium (Na+) through the **Na+-K+-2Cl- cotransporter (NKCC2)**, also known as the bumetanide-sensitive cotransporter. This transporter is crucial for the countercurrent multiplication process that helps to concentrate the urine. It reabsorbs Na+, K+, and Cl- ions in a 1:1:2 ratio.

## Why Each Wrong Option is Incorrect
- **Option A:** Incorrect because it does not accurately represent the percentage of Na+ reabsorbed or specify the transporter.
- **Option B:** Incorrect because, although it mentions a transporter, the percentage and details might not align with the NKCC2's role in the TAL.
- **Option D:** Incorrect because it inaccurately represents either the percentage of Na+ reabsorbed or the transporter involved.

## Clinical Pearl / High-Yield Fact
A key point to remember is that **loop diuretics** (e.g., furosemide, bumetanide) act by inhibiting the **NKCC2** transporter in the thick ascending limb of the loop of Henle, which leads to decreased sodium, chloride, and water reabsorption and, consequently, increased urine output. This is critical in managing conditions like heart failure and edema.

## Correct Answer Line
**Correct Answer: C.**