**Core Concept**
The discoloration of urine is a result of various substances that can alter its normal yellow color. Green-colored urine is a specific condition that can arise due to the presence of certain compounds or medications.

**Why the Correct Answer is Right**
Green-colored urine is typically seen in patients with a condition known as Lederer's sign or 'fluorescein urochrome.' This phenomenon occurs when there is an accumulation of urochrome, a green pigment, in the urine. Urochrome is a degradation product of hemoglobin, which can be excessive in cases of hemolytic anemia, liver dysfunction, or certain infections. The presence of urochrome in the urine can give it a characteristic greenish hue.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because green-colored urine is not a common side effect of most antibiotics, except in rare cases where they induce hemolysis. The specific antibiotics that can cause hemolysis are typically those that contain a sulfonamide group.
**Option B:** This option is incorrect because bilirubin is responsible for yellow-colored urine, not green. Bilirubin is a byproduct of heme degradation and can accumulate in conditions like jaundice.
**Option C:** This option is incorrect because certain medications like rifampicin can cause orange or red urine due to its lipophilic nature and ability to bind to proteins in the urine.

**Clinical Pearl / High-Yield Fact**
It is essential to note that the color of urine can provide valuable clues to underlying conditions. A greenish tint to the urine, known as Lederer's sign, can indicate the presence of urochrome, which may be a sign of hemolytic anemia or liver dysfunction.

**Correct Answer:** D.