## **Core Concept**
Topical sulfonamides are a class of antimicrobials used to treat infections on the skin or in the eyes. They work by inhibiting folic acid synthesis in bacteria. Sulfonamides are often used in combination with other agents to broaden their antimicrobial spectrum.

## **Why the Correct Answer is Right**
The correct answer, **C. Mafenide acetate**, is a topical sulfonamide used primarily for the treatment of burns. It has a broad spectrum of activity, including against *Pseudomonas aeruginosa*. Mafenide acetate works by inhibiting bacterial dihydropteroate synthetase, an enzyme necessary for folic acid synthesis. This action is bacteriostatic, but at higher concentrations, it can be bactericidal.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option does not correspond to a commonly recognized topical sulfonamide.
- **Option B:** This option does not match a well-known topical sulfonamide used in clinical practice.
- **Option D:** This option does not represent a topical sulfonamide; sulfacetamide, however, is another sulfonamide used topically, particularly in eye drops.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that mafenide acetate can cause pain upon application and may lead to metabolic acidosis due to its carbonic anhydrase inhibitory activity. It's specifically used for severe burns to prevent infection.

## **Correct Answer:** C. Mafenide acetate.