**Core Concept**
Digoxin is a cardiac glycoside used to treat heart failure and arrhythmias. Its toxicity can occur due to various factors affecting its pharmacokinetics, including renal impairment, electrolyte imbalances, and drug interactions.

**Why the Correct Answer is Right**
Digoxin is primarily excreted by the kidneys. In patients with renal impairment, digoxin accumulation occurs because the reduced glomerular filtration rate leads to decreased clearance of the drug. This results in elevated digoxin levels, increasing the risk of toxicity, especially in the context of hypokalemia (low potassium levels) and hypomagnesemia (low magnesium levels), which can further potentiate digoxin's effects on the heart.

**Why Each Wrong Option is Incorrect**
* **Option A:** While liver disease can affect the metabolism of various drugs, it does not significantly impact digoxin clearance. Digoxin is primarily excreted by the kidneys, making renal impairment a more critical factor in its toxicity.
* **Option B:** Electrolyte imbalances, particularly hypokalemia and hypomagnesemia, can contribute to digoxin toxicity, but they are not the primary cause of its accumulation. Instead, they can exacerbate the effects of digoxin on the heart.
* **Option C:** Age does not directly affect digoxin clearance. Elderly patients may be more susceptible to digoxin toxicity due to decreased renal function and increased sensitivity to the drug's effects.

**Clinical Pearl / High-Yield Fact**
Remember the acronym "KILL" to associate with digoxin toxicity: K+ (hypokalemia), I (increased age), L (low magnesium levels), and L (renal impairment leading to decreased clearance).

**Correct Answer: B. Electrolyte imbalances.**