**Core Concept**
A deviated nasal septum (DNS) is a condition where the thin wall of cartilage and bone between the nostrils is significantly displaced, causing breathing difficulties and other problems. This condition can be caused by trauma, genetics, or other factors.

**Why the Correct Answer is Right**
Surgery is required for DNS when the deviation is significant enough to cause nasal obstruction, recurrent nasal bleeding, or other complications. The goal of surgery is to correct the deviation and restore normal nasal function. This is typically achieved through a procedure called septoplasty, where the deviated septum is repositioned or removed to improve breathing and alleviate symptoms.

**Why Each Wrong Option is Incorrect**
**Option A:** DNS is not typically treated with antibiotics, as it is a structural issue rather than an infection.
**Option B:** DNS may not require surgery if it is not causing significant symptoms or complications.
**Option C:** DNS is not usually treated with nasal decongestants, as they only provide temporary relief and do not address the underlying issue.

**Clinical Pearl / High-Yield Fact**
A key factor in deciding whether to operate on a DNS is the presence of significant nasal obstruction or recurrent bleeding, as these symptoms can significantly impact a patient's quality of life.

**Correct Answer: C.**