## **Core Concept**
The question tests knowledge of cephalosporins' pharmacokinetics, specifically their handling in patients with renal impairment. Cephalosporins are a class of β-lactam antibiotics, and their elimination is often affected by renal function. Some cephalosporins require dose adjustment in patients with renal impairment to prevent accumulation and potential toxicity.

## **Why the Correct Answer is Right**
Cefepime is primarily excreted unchanged in the urine. However, among the given options, **Ceftriaxone** stands out because it is primarily eliminated via the biliary system into the feces, with only a small fraction excreted in the urine. This unique elimination profile makes ceftriaxone less dependent on renal excretion, and thus, it does not require dose adjustment in patients with renal impairment.

## **Why Each Wrong Option is Incorrect**
- **Option A:** Although specific details are not provided for option A, many cephalosporins are primarily excreted by the kidneys and require dose adjustments in renal impairment.
- **Option B:** Similarly, without specifics, most cephalosporins that are mainly renally excreted will need dose adjustments.
- **Option D:** This option would also likely require dose adjustment if it is primarily excreted by the kidneys.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that **ceftriaxone** is unique among cephalosporins for its primarily non-renal elimination, making it a convenient choice for patients with renal impairment. This characteristic can be critical in clinical settings where patients have varying degrees of kidney function.

## **Correct Answer:** C. Ceftriaxone