**Core Concept**
Nitric oxide (NO) is a crucial signaling molecule involved in various physiological processes, including vasodilation, neurotransmission, and immune response. It plays a significant role in maintaining vascular tone, particularly in the regulation of blood pressure.

**Why the Correct Answer is Right**
Nitric oxide exerts its vasodilatory effects by stimulating the production of cyclic guanosine monophosphate (cGMP) in vascular smooth muscle cells. This occurs through the activation of guanylate cyclase, an enzyme that catalyzes the conversion of guanosine triphosphate (GTP) to cGMP. The increase in cGMP levels leads to the relaxation of vascular smooth muscle, resulting in vasodilation. This mechanism is mediated by the soluble guanylate cyclase enzyme, which is activated by the binding of NO to its heme group.

**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect, as it does not accurately describe the mechanism of action of nitric oxide.
**Option B:** Incorrect, as it is a different signaling molecule involved in a different physiological process.
**Option C:** Incorrect, as it refers to a different enzyme involved in a different biochemical pathway.

**Clinical Pearl / High-Yield Fact**
Nitric oxide is synthesized from the amino acid L-arginine by the enzyme nitric oxide synthase (NOS), which exists in different isoforms, including endothelial NOS (eNOS), neuronal NOS (nNOS), and inducible NOS (iNOS).

**Correct Answer:** C.