**Core Concept**
The question is testing the physiological response to moderate cold exposure. The underlying principle is the activation of specific receptors that help the body adapt to cold temperatures, leading to vasoconstriction and heat conservation.

**Why the Correct Answer is Right**
When exposed to moderate cold, the body activates the sympathetic nervous system, which stimulates the release of catecholamines (e.g., norepinephrine). These catecholamines bind to alpha-adrenergic receptors, particularly alpha-2 (α2) receptors, on the smooth muscle cells of blood vessels. Activation of these receptors leads to vasoconstriction, reducing blood flow to peripheral tissues and conserving heat in the core. This response helps maintain core body temperature during cold exposure.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because the stimulation of beta-adrenergic receptors (β1, β2, or β3) would lead to vasodilation, not vasoconstriction.
* **Option B:** This option is incorrect because the stimulation of muscarinic receptors by acetylcholine would lead to vasodilation and increased heart rate, not vasoconstriction.
* **Option C:** This option is incorrect because the stimulation of dopamine receptors would have various effects depending on the receptor subtype, but vasoconstriction is not a primary response to moderate cold exposure.

**Clinical Pearl / High-Yield Fact**
Cold exposure activates the sympathetic nervous system, leading to vasoconstriction and heat conservation. This response is mediated by the release of catecholamines, which stimulate alpha-2 receptors on blood vessel smooth muscle cells.

**Correct Answer: C.