**Question:** Decarboxylation of which of the following amino acids results in formation of a vasodilator:

A. L-Arginine
B. L-Histidine
C. L-Tyrosine
D. L-Tryptophan

**Core Concept:** Decarboxylation is a chemical reaction that involves the removal of a carbon dioxide (CO2) group from an organic molecule, often leading to the formation of a carboxylate ion and release of CO2 gas. In the context of this question, decarboxylation refers to the removal of CO2 from specific amino acids.

**Why the Correct Answer is Right:** The correct answer, L-Arginine, is an essential amino acid that plays a crucial role in various physiological processes. The decarboxylation of L-Arginine results in the release of Citrulline and CO2 gas, which ultimately leads to the formation of Nitric Oxide (NO). NO is a potent vasodilator that helps in dilating blood vessels, increasing blood flow, and regulating blood pressure.

**Why Each Wrong Option is Incorrect:**

**Option A (L-Histidine):** Histidine is an amino acid involved in the synthesis of histamine, a compound that can cause vasoconstriction (narrowing of blood vessels) rather than vasodilation (dilating blood vessels).

**Option C (L-Tyrosine):** Tyrosine is an essential amino acid involved in the synthesis of proteins and neurotransmitters, but does not directly result in the formation of a vasodilator.

**Option D (L-Tryptophan):** Tryptophan is an essential amino acid involved in the synthesis of serotonin and melatonin, neurotransmitters that do not directly result in the formation of a vasodilator.

**Core Concept:** Vasodilation refers to the process of increasing the diameter of blood vessels, which improves blood flow and lowers blood pressure. Vasoconstriction, on the other hand, narrows blood vessels and raises blood pressure.

**Why Each Wrong Option is Incorrect:**

**Option A (L-Histidine):** Histidine is involved in the synthesis of histamine, which is a vasoconstrictor, narrowing of blood vessels, and increasing blood pressure.

**Option C (L-Tyrosine):** Tyrosine is involved in the synthesis of proteins and neurotransmitters, but does not directly result in the formation of a vasodilator.

**Option D (L-Tryptophan):** Tryptophan is involved in the synthesis of serotonin and melatonin, neurotransmitters that do not directly result in the formation of a vasodilator.

**Core Concept:** Decarboxylation is the process of removing a carboxyl group (COOH) from an organic molecule, often leading to the formation of a carboxylate ion. In the context of this question, decarboxylation of L-Arginine produces nitric oxide (NO), which is a potent vasodilator.

**Why the Correct Answer is Right:**

Arginine is a