**Core Concept**
Administering prophylactic antibiotics in the correct timing is crucial to prevent surgical site infections (SSIs) in patients undergoing surgical procedures. The optimal timing of antibiotic administration is based on the understanding of bacterial colonization, host defense mechanisms, and the pharmacokinetics of the antibiotic.

**Why the Correct Answer is Right**
The optimal timing of prophylactic antibiotic administration is within 60 minutes before the surgical incision. This timing allows for adequate tissue concentrations of the antibiotic at the time of incision, thereby reducing the risk of SSI. The antibiotic should be given after the patient has been positioned for surgery and before the surgical site is prepared and draped. This approach ensures that the antibiotic is present in the tissues at the time of incision, thereby providing optimal prophylaxis against SSI.

**Why Each Wrong Option is Incorrect**
**Option A:** Administering antibiotics more than 120 minutes before the surgical incision may lead to suboptimal tissue concentrations at the time of incision, increasing the risk of SSI.

**Option B:** Delaying antibiotic administration until after the surgical incision may allow bacteria to colonize the surgical site, making it more challenging to prevent SSI.

**Option C:** Administering antibiotics too close to the end of the surgical procedure may result in suboptimal tissue concentrations, reducing the effectiveness of the antibiotic in preventing SSI.

**Clinical Pearl / High-Yield Fact**
To optimize the timing of prophylactic antibiotic administration, it is essential to consider the type of surgical procedure, the antibiotic used, and the patient's underlying medical conditions. A common mnemonic to remember the optimal timing is "60 minutes before, within 60 minutes after" the incision.

**Correct Answer:** C.