**Core Concept**
Digoxin, furosemide, and hydralazine are three primary classes of drugs used in the management of congestive heart failure (CHF). Digoxin increases the force of cardiac contractions, furosemide is a diuretic that reduces fluid overload, and hydralazine is a vasodilator that reduces afterload. However, one of these drugs is not primarily indicated for CHF.

**Why the Correct Answer is Right**
Hydralazine is often used in combination with nitrates for the treatment of hypertension and heart failure. However, its primary indication is not for the treatment of CHF. It is often used as an alternative for patients with CHF who are intolerant to ACE inhibitors or ARBs, particularly in African American patients. In contrast, digoxin and furosemide are both commonly used in the initial management of CHF.

**Why Each Wrong Option is Incorrect**
**Option A:** Digoxin is a useful agent in CHF for increasing the force of cardiac contractions and controlling ventricular rate in atrial fibrillation.
**Option B:** Furosemide is a loop diuretic that reduces fluid overload in CHF, making it an essential component of CHF management.
**Option C:** (This option is missing, so I'll leave it blank)

**Clinical Pearl / High-Yield Fact**
When using digoxin in CHF, it's essential to monitor its levels and be aware of the narrow therapeutic index, as toxicity can occur at levels close to the therapeutic range.

**Correct Answer:** C.