**Core Concept**
Vasoconstriction refers to the narrowing of blood vessels, which increases blood pressure and resistance to blood flow. This physiological response is mediated by the sympathetic nervous system and involves the release of vasoconstrictor substances.

**Why the Correct Answer is Right**
The correct answer involves the sympathetic nervous system's release of norepinephrine (NE) and epinephrine (EPI), which act on alpha-1 adrenergic receptors (α1-ARs) on vascular smooth muscle cells. Activation of these receptors leads to an increase in intracellular calcium, resulting in muscle contraction and vasoconstriction. Additionally, endothelin-1 (ET-1), a potent vasoconstrictor peptide, is released from endothelial cells and acts on ET receptors on vascular smooth muscle cells, contributing to vasoconstriction.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not specify a vasoconstrictor substance or mechanism.
**Option B:** This option is incorrect because it does not correctly identify the primary vasoconstrictor substance or receptor involved.
**Option C:** This option is incorrect because it is a vasodilator, which would cause blood vessels to widen, not constrict.

**Clinical Pearl / High-Yield Fact**
The α1-AR agonist, phenylephrine, is often used as a nasal decongestant due to its ability to cause local vasoconstriction, reducing nasal congestion.

**Correct Answer: D. Norepinephrine and epinephrine acting on alpha-1 adrenergic receptors.**