## Core Concept
Pheochromocytomas are rare tumors that arise from the chromaffin cells of the adrenal medulla. The primary clinical manifestations of pheochromocytoma are due to the excessive secretion of catecholamines, which are hormones produced by these cells. The main catecholamines secreted are **epinephrine (adrenaline)** and **norepinephrine (noradrenaline)**.

## Why the Correct Answer is Right
The correct answer involves the understanding that pheochromocytomas secrete catecholamines, primarily **epinephrine** and **norepinephrine**. These hormones cause the classic symptoms of pheochromocytoma, including hypertension, tachycardia, sweating, and palpitations. The secretion of these catecholamines leads to the activation of **alpha** and **beta-adrenergic receptors**, resulting in the clinical manifestations.

## Why Each Wrong Option is Incorrect
- **Option A:** This option is incorrect because it does not specify the correct hormones associated with pheochromocytoma.
- **Option B:** This option is incorrect for similar reasons as option A; it does not accurately represent the primary hormones secreted by pheochromocytomas.
- **Option C:** This option might be considered partially correct in that pheochromocytomas do secrete catecholamines, but without specifying **epinephrine** and **norepinephrine**, it's not accurate.

## Clinical Pearl / High-Yield Fact
A key clinical pearl is that the **rule of 10s** can be remembered for pheochromocytomas: 10% are bilateral, 10% are extra-adrenal (paragangliomas), 10% are malignant, and 10% are familial. Additionally, a classic clinical feature is the **paroxysmal hypertension** that patients experience.

## Correct Answer Line
**Correct Answer: D.** Epinephrine and Norepinephrine.