**Core Concept:**
Phase-2 reactions refer to a series of chemical modifications that take place in the liver during drug detoxification. These reactions involve the conjugation of polar molecules (such as glucuronic acid, sulfate, or glutathione) onto the parent compound, making it more water-soluble and facilitating excretion.

**Why the Correct Answer is Right:**
Phase-2 reactions are crucial for the liver's detoxification process. In this case, the correct answer is **D**. The correct option indicates the process of glucuronidation, where the glucuronic acid molecule is attached to the parent compound. This conjugation makes the drug more water-soluble, allowing it to be excreted more easily by the kidneys and reducing its toxicity.

**Why Each Wrong Option is Incorrect:**
A. **Option A (Sulfation):** This refers to the attachment of sulfate groups to the parent compound, but it is less common than glucuronidation and not as effective in increasing water solubility.
B. **Option B (Glutathionation):** This is incorrect as it involves the attachment of glutathione, which is not a common conjugation molecule.
C. **Option C (Amination):** This refers to the covalent bonding of ammonia groups to the parent compound, which is not a phase-2 reaction.

**Clinical Pearl / High-Yield Fact:**
Understanding phase-2 reactions is essential for understanding drug interactions, side effects, and the mechanism behind drug clearance. A deep understanding of these reactions helps in predicting potential adverse reactions and drug-drug interactions.