**Core Concept**
Potassium absorption in the nephron occurs primarily in the proximal convoluted tubule (PCT) and the loop of Henle. The majority of filtered potassium is reabsorbed in the PCT, with a smaller fraction reabsorbed in the Henle's loop.

**Why the Correct Answer is Right**
Potassium reabsorption in the PCT is largely driven by the sodium-potassium pump (Na+/K+-ATPase) and the sodium gradient generated by the sodium-hydrogen exchanger (NHE3). The sodium gradient helps to drive potassium reabsorption, which is essential for maintaining potassium balance and preventing hypokalemia. The PCT is highly efficient in reabsorbing potassium, with approximately 65-70% of filtered potassium being reabsorbed in this segment.

**Why Each Wrong Option is Incorrect**
- **Option A:** The distal convoluted tubule (DCT) is primarily responsible for potassium secretion, not reabsorption. The DCT is where potassium is secreted into the lumen in exchange for sodium reabsorption.
- **Option B:** The collecting duct is not a major site of potassium reabsorption. While potassium can be reabsorbed in the collecting duct, it is largely under the influence of aldosterone, which promotes potassium secretion.
- **Option C:** The loop of Henle does reabsorb some potassium, but not to the same extent as the PCT. Potassium reabsorption in the loop of Henle is largely driven by the sodium-potassium-chloride cotransporter (NKCC2).

**Clinical Pearl / High-Yield Fact**
The majority of potassium reabsorption occurs in the PCT, making it a crucial site for potassium balance regulation. Understanding the mechanisms of potassium reabsorption is essential for managing patients with potassium disorders, such as hypokalemia or hyperkalemia.

**Correct Answer: C. The loop of Henle.**