**Core Concept**
Zero-order kinetics refers to the pharmacokinetic process where the rate of drug elimination is independent of the drug concentration. This occurs when the enzyme responsible for metabolizing the drug is saturated, and an increase in drug concentration does not lead to an increase in the rate of metabolism.

**Why the Correct Answer is Right**
Zero-order kinetics is typically observed in drugs that are metabolized by a single enzyme, and this enzyme is saturated at low concentrations of the drug. An example of such a drug is ethanol, which is metabolized by alcohol dehydrogenase. When the enzyme is saturated, the rate of ethanol metabolism becomes independent of the concentration, following zero-order kinetics.

**Why Each Wrong Option is Incorrect**
* **Option A:**
This option is incorrect because it does not exhibit zero-order kinetics. The metabolism of this drug is dependent on its concentration, and an increase in concentration leads to an increase in the rate of metabolism, following first-order kinetics.
* **Option B:**
This option is incorrect because it does not exhibit zero-order kinetics. The metabolism of this drug is dependent on its concentration, and an increase in concentration leads to an increase in the rate of metabolism, following first-order kinetics.
* **Option C:**
This option is incorrect because it does not exhibit zero-order kinetics. The metabolism of this drug is dependent on its concentration, and an increase in concentration leads to an increase in the rate of metabolism, following first-order kinetics.

**Clinical Pearl / High-Yield Fact**
Drugs that exhibit zero-order kinetics may require more frequent dosing to maintain therapeutic concentrations, as the rate of elimination is constant and not dependent on the concentration.

**Correct Answer: D.**