**Core Concept**
The empirical use of intravenous amphotericin B involves administering the drug to a patient with suspected or confirmed fungal infection before the causative organism is identified. This approach is based on the broad-spectrum antifungal activity of amphotericin B, which is effective against a wide range of fungal pathogens.

**Why the Correct Answer is Right**
Amphotericin B works by binding to the sterol component of fungal cell membranes, ultimately leading to cell lysis and death. The drug's mechanism of action involves the formation of a channel in the cell membrane, causing an influx of sodium ions and subsequent cell death. In the absence of definitive diagnosis, empirical therapy with amphotericin B is initiated to rapidly control the infection and prevent further complications.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not provide a specific indication for empirical use of intravenous amphotericin B.
**Option B:** This option is incorrect as it is not a common indication for empirical use of intravenous amphotericin B.
**Option C:** This option is incorrect as it is not a specific indication for empirical use of intravenous amphotericin B.

**Clinical Pearl / High-Yield Fact**
When initiating empirical therapy with amphotericin B, it is essential to monitor serum creatinine and potassium levels closely, as the drug can cause nephrotoxicity and hypokalemia.

**Correct Answer:** C. Candidemia or suspected invasive candidiasis in a critically ill patient.