**Core Concept**
The question is testing the ability to identify bacteria that produce urease, an enzyme that breaks down urea into carbon dioxide and ammonia. Urease production is a key characteristic used in the identification of certain bacteria, particularly those that cause urinary tract infections.

**Why the Correct Answer is Right**
Urease-positive bacteria, such as Proteus, Klebsiella, and Morganella, produce the enzyme urease, which catalyzes the hydrolysis of urea to form ammonia and carbon dioxide. This reaction is responsible for the characteristic "alkaline" or "foul" odor of urine in patients infected with these bacteria. The presence of urease can be detected using the Christensen's urea agar test, which detects the production of ammonia.

**Why Each Wrong Option is Incorrect**
**Option A:** Proteus is actually urease-positive, so this option is incorrect.
**Option B:** Klebsiella is also urease-positive, so this option is incorrect.
**Option C:** Morganella is a urease-positive bacterium, so this option is incorrect.

**Clinical Pearl / High-Yield Fact**
When suspecting a urinary tract infection, it is essential to remember that urease-positive bacteria can cause alkaline urine, which can lead to the formation of kidney stones.

**Correct Answer:** D.