**Core Concept**
The kidneys play a crucial role in maintaining acid-base balance and ammonia production is a key aspect of this process. The enzyme glutaminase in the renal tubules catalyzes the conversion of glutamine to glutamate and ammonia, which is then excreted in the urine.

**Why the Correct Answer is Right**
The correct answer is glutamine because it is the primary amino acid responsible for producing ammonia in the kidneys. This process is mediated by the enzyme glutaminase, which is present in the renal tubular cells. Glutamine is converted to glutamate and ammonia through a two-step reaction, with glutaminase being the rate-limiting enzyme. The ammonia produced is then excreted in the urine, helping to maintain acid-base balance.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not specify the correct amino acid responsible for ammonia production in the kidneys.
* **Option B:** This option is incorrect because it is not a correct amino acid associated with ammonia production in the kidneys.
* **Option D:** This option is incorrect because it is not a correct amino acid associated with ammonia production in the kidneys.

**Clinical Pearl / High-Yield Fact**
Glutaminase inhibitors, such as methanol and acetaldehyde, can decrease ammonia production and lead to hyperammonemia, a condition characterized by elevated levels of ammonia in the blood.

**Correct Answer: D. Glutamine**