**Core Concept**
Digoxin is a cardiac glycoside used in the treatment of heart failure and atrial fibrillation. Its pharmacokinetics is crucial in determining the optimal dosing and monitoring of the drug. The half-life of a drug is the time it takes for the plasma concentration to reduce by half.

**Why the Correct Answer is Right**
The half-life of digoxin is approximately 1.9 days (40 hours) in patients with normal renal function. This is due to its elimination primarily through the kidneys, with a small amount metabolized in the liver. The half-life of digoxin can be affected by factors such as renal impairment, age, and concomitant medications, which can alter its clearance and consequently its half-life.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the half-life of digoxin is not around 6-8 hours, which would be more typical of a drug with a shorter elimination half-life.
**Option B:** This option is incorrect because the half-life of digoxin is not around 12-14 hours, which would be more typical of a drug with a moderate elimination half-life.
**Option C:** This option is incorrect because the half-life of digoxin is not around 24-28 hours, which would be more typical of a drug with a long elimination half-life.

**Clinical Pearl / High-Yield Fact**
It's essential to note that digoxin has a narrow therapeutic window, and its half-life can be affected by various factors. Therefore, monitoring of digoxin levels is crucial to prevent toxicity.

**Correct Answer: C. 1.9 days**