**Core Concept**
Functional Endoscopic Sinus Surgery (FESS) is a minimally invasive surgical procedure used to treat various sinus and nasal disorders. It involves the removal of diseased or damaged tissue from the sinuses using an endoscope and specialized instruments.

**Why the Correct Answer is Right**
FESS is indicated in cases of chronic sinusitis, nasal polyps, septal deviation, and other conditions that cause nasal obstruction or sinusitis. The procedure allows for the removal of diseased tissue, improvement of sinus drainage, and reduction of nasal congestion. The endoscope provides a clear view of the sinuses, enabling precise removal of affected tissue and preservation of surrounding healthy tissue.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is likely incorrect as it is not a specific indication for FESS. Without further information, it is difficult to determine the validity of this option.
**Option B:** This option may be a treatment option for certain conditions, but it is not a specific indication for FESS. FESS is a surgical procedure, and this option does not indicate a specific surgical indication.
**Option C:** This option is likely incorrect as it is not a specific indication for FESS. Without further information, it is difficult to determine the validity of this option.

**Clinical Pearl / High-Yield Fact**
FESS is often used to treat conditions that cause nasal obstruction or sinusitis, and it is a valuable tool for preserving healthy tissue and improving sinus drainage.

**Correct Answer:** C. Nasal polyps.