**Core Concept**
First-generation cephalosporins are primarily effective against gram-positive bacteria and have limited activity against gram-negative organisms. They are commonly used in surgical prophylaxis due to their safety profile, good tissue penetration, and broad coverage of skin flora.

**Why the Correct Answer is Right**
Cefazolin is a first-generation cephalosporin with strong activity against *Staphylococcus aureus* and other gram-positive bacteria, which are the most common pathogens in surgical site infections. It is widely recommended for surgical prophylaxis due to its favorable pharmacokinetics, low risk of allergies, and proven efficacy in reducing postoperative infection rates. It is also well-tolerated and has a long half-life, allowing for single-dose administration preoperatively.

**Why Each Wrong Option is Incorrect**
Option A: Ceftriaxone is a third-generation cephalosporin with broader gram-negative coverage, including *Enterobacter* and *Neisseria*, and is not typically used for routine surgical prophylaxis due to higher cost and potential for resistance.
Option B: Cefoxitin is a second-generation cephalosporin with activity against some gram-negative bacteria and anaerobes, but it is not classified as first-generation and is used more in intra-abdominal infections or complicated cases.
Option D: Cefepime is a fourth-generation cephalosporin with enhanced gram-negative coverage and is used for serious infections, not routine surgical prophylaxis.

**Clinical Pearl / High-Yield Fact**
Cefazolin is the **first-line first-generation cephalosporin** for surgical prophylaxis, especially in clean surgeries involving skin flora. Always check patient allergy history before use, as it can cause hypersensitivity, though less than penicillins.

✓ Correct Answer: C. Cefazolin