**Core Concept:** Type A disorders are a classification of cardiovascular disorders characterized by elevated blood pressure and increased sympathetic nervous system activity. They are further divided into primary and secondary causes.

**Why the Correct Answer is Right:**
The correct answer, **C. Hypertension**, is a type of Type A disorder. Hypertension is defined as having a consistently elevated blood pressure (BP) above normal levels. In primary hypertension (essential hypertension), the cause remains unknown and is attributed to a combination of genetic and lifestyle factors. This is distinct from secondary hypertension, where hypertension is caused by an identifiable underlying medical condition, such as kidney disease or cardiovascular disease.

**Why Each Wrong Option is Incorrect:**
A. **Angina pectoris (Option A)** is a condition characterized by chest pain caused by reduced blood flow to the heart muscle due to coronary artery disease. It is not a type of Type A disorder.
B. **Heart failure (Option B)** is a condition where the heart is unable to pump blood efficiently, often resulting in fluid accumulation and shortness of breath. It is a type of Type B disorder (cardiovascular disorder) and not a Type A disorder.
D. **Atrial fibrillation (Option D)** is a type of arrhythmia characterized by irregular and abnormally fast heartbeat. It is a Type B disorder (cardiovascular disorder) and not a Type A disorder.

**Clinical Pearl:**
Type A disorders focus on cardiovascular issues caused by increased sympathetic activity, while Type B disorders involve abnormalities in heart structure or function. Understanding the difference between these two types aids in determining appropriate treatment strategies and patient management.

**Correct Answer:** C. Hypertension