**Core Concept**
Dopamine is a catecholamine with dose-dependent effects on the cardiovascular system. At low doses, it stimulates dopamine receptors in the renal and mesenteric arteries, causing vasodilation and increased blood flow. This effect is particularly beneficial in patients with acute kidney injury or shock.

**Why the Correct Answer is Right**
The correct dose for renal vasodilatation is typically between 1-3 mcg/kg/min. At this dose, dopamine activates D1 receptors in the renal arteries, leading to vasodilation and increased renal blood flow. This increase in blood flow helps to improve renal function and glomerular filtration rate in patients with acute kidney injury. The D1 receptor-mediated effect is thought to be responsible for the beneficial effects of dopamine on renal function.

**Why Each Wrong Option is Incorrect**
**Option A:** This dose of dopamine is typically used for cardiac inotropic support, which is not the primary goal in this scenario.
**Option B:** This dose is associated with increased systemic vascular resistance and vasoconstriction, which is not desirable for renal vasodilatation.
**Option C:** This dose is often used for anxiolysis and sedation, which is unrelated to the goal of renal vasodilatation.

**Clinical Pearl / High-Yield Fact**
Remember that dopamine's effects are dose-dependent, and the same dose that increases heart rate and blood pressure at higher doses can actually decrease systemic vascular resistance and increase renal blood flow at lower doses.

**Correct Answer: C. 2-5 mcg/kg/min**