**Core Concept**
Dobutamine is a synthetic catecholamine that acts as a beta-1 agonist, increasing heart rate and contractility, and as a beta-2 agonist, causing vasodilation. The goal in treating acute cardiac failure is to improve cardiac output and reduce afterload.

**Why the Correct Answer is Right**
In the absence of dobutamine, a combination of dopamine and norepinephrine could be used to achieve a similar effect. Dopamine, at low doses, acts as a beta-1 agonist, increasing heart rate and contractility, similar to dobutamine. At higher doses, dopamine also acts as a vasopressor, increasing vascular tone. Norepinephrine, a potent alpha-1 agonist, increases vascular tone and afterload, allowing the heart to pump more effectively against the increased resistance. This combination would provide the equivalent pharmacologic effect of dobutamine.

**Why Each Wrong Option is Incorrect**
**Option A:** Epinephrine is a non-selective alpha and beta agonist, which could increase afterload and worsen cardiac failure.
**Option B:** Furosemide is a diuretic that reduces fluid overload but does not directly increase cardiac contractility or output.
**Option C:** Metoprolol is a beta-blocker that would decrease heart rate and contractility, exacerbating cardiac failure.

**Clinical Pearl / High-Yield Fact**
When using dopamine and norepinephrine together, start with low doses of dopamine (2-5 mcg/kg/min) and titrate upwards as needed, while concurrently adjusting norepinephrine doses to avoid excessive vasopressor effects.

**Correct Answer:** D.