**Core Concept**
Primary hyperaldosteronism is a condition characterized by excessive production of aldosterone, a hormone produced by the adrenal glands that regulates fluid balance and blood pressure. This condition leads to hypertension, hypokalemia, and metabolic alkalosis.

**Why the Correct Answer is Right**
Primary hyperaldosteronism is often caused by an aldosterone-producing adenoma, which secretes excess aldosterone. This hormone acts on the kidneys to retain sodium and water, leading to increased blood volume and pressure. The increased aldosterone levels also lead to potassium excretion, resulting in hypokalemia. Additionally, the body's response to the excess aldosterone leads to metabolic alkalosis, characterized by an increase in blood pH.

**Why Each Wrong Option is Incorrect**
* **Option A:** Hypokalemia is actually a feature of primary hyperaldosteronism, not an exception.
* **Option B:** Metabolic alkalosis is also a characteristic of primary hyperaldosteronism, making it an incorrect choice as an exception.
* **Option C:** Hypertension is a common presentation of primary hyperaldosteronism, so it's not the correct answer.

**Clinical Pearl / High-Yield Fact**
Aldosterone-producing adenomas are typically small and benign, but they can cause significant clinical consequences due to the excess hormone production.

**Correct Answer:** C. Hypertension is a feature of primary hyperaldosteronism.