**Core Concept**
The question is testing the student's knowledge of antiarrhythmic medications used to treat arrhythmias. Antiarrhythmic drugs are classified into four main groups based on their mechanism of action: Class I (sodium channel blockers), Class II (beta blockers), Class III (potassium channel blockers), and Class IV (calcium channel blockers).

**Why the Correct Answer is Right**
The correct answer is the drug that does not belong to the oral treatment category for arrhythmia. Oral medications are preferred for long-term management of arrhythmias due to their ease of administration and compliance. However, some antiarrhythmic medications are administered intravenously due to their potential toxicity or rapid onset of action.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it is a common oral antiarrhythmic medication used to treat various types of arrhythmias, including atrial fibrillation and ventricular tachycardia.
**Option B:** This option is incorrect because it is an oral beta blocker used to treat arrhythmias, hypertension, and heart failure.
**Option C:** This option is incorrect because it is a Class I antiarrhythmic medication that can be administered orally to treat certain types of arrhythmias.

**Clinical Pearl / High-Yield Fact**
When choosing an oral antiarrhythmic medication, it is essential to consider the patient's underlying heart condition, concomitant medications, and potential side effects.

**Correct Answer:** D.