**Core Concept**
Left axis deviation (LAD) is a type of electrocardiographic (ECG) abnormality characterized by a QRS axis between -30° and -60°, indicating a leftward deviation of the electrical activity of the heart. This is often associated with left ventricular hypertrophy or bundle branch blocks.

**Why the Correct Answer is Right**
Left axis deviation is caused by a delay in electrical conduction through the left bundle branch, which can be due to various conditions such as left ventricular hypertrophy, coronary artery disease, or cardiomyopathies. The electrical activity of the left ventricle is delayed, resulting in a leftward deviation of the QRS axis. This can lead to changes in the ECG, including a prolonged QRS duration and a leftward shift of the QRS axis.

**Why Each Wrong Option is Incorrect**
* **Option A:** Right axis deviation (RAD) is characterized by a QRS axis between 100° and 180°, which is opposite of left axis deviation.
* **Option B:** This option is not provided.
* **Option C:** This option is not provided.

**Clinical Pearl / High-Yield Fact**
It's essential to note that left axis deviation can be a marker of underlying cardiac pathology, and a thorough evaluation is necessary to determine the cause. A left axis deviation of -30° to -60° on an ECG should prompt further investigation, such as echocardiography or coronary angiography, to rule out significant cardiac disease.

**Correct Answer: C. Left axis deviation is seen in conditions such as left ventricular hypertrophy or bundle branch blocks.**