**Core Concept**
Anti-arrhythmic drugs are classified into four main categories (I-IV) based on their mechanism of action. Class Ic anti-arrhythmic drugs are a subset of Class I drugs, which primarily work by blocking sodium channels in cardiac cells, thereby prolonging the effective refractory period and reducing the rate of rise of the action potential.

**Why the Correct Answer is Right**
Class Ic anti-arrhythmic drugs, such as propafenone and flecainide, have a high affinity for the sodium channel and a slow rate of dissociation, which leads to a marked decrease in the rate of rise of the action potential and a significant prolongation of the effective refractory period. This effect is specific to the cardiac sodium channels and is responsible for their anti-arrhythmic properties.

**Why Each Wrong Option is Incorrect**
**Option A:** **Flecainide** is a Class Ic anti-arrhythmic drug, so it is not the correct answer.
**Option B:** **Propafenone** is also a Class Ic anti-arrhythmic drug, so it is not the correct answer.
**Option C:** **Quinidine** is a Class Ia anti-arrhythmic drug, which has a different mechanism of action compared to Class Ic drugs. It primarily blocks sodium channels, but also has a significant effect on potassium channels.

**Clinical Pearl / High-Yield Fact**
When selecting an anti-arrhythmic drug, it is essential to consider the specific type of arrhythmia being treated, as well as the patient's underlying cardiac conditions and other medications. Class Ic anti-arrhythmic drugs are often used to treat supraventricular tachycardias, but can be contraindicated in patients with certain types of Wolff-Parkinson-White syndrome.

**Correct Answer:** C. Quinidine is a Class Ia anti-arrhythmic drug.