**Core Concept**
A common complication following appendectomy is related to the management of the stump, where the appendix is ligated and removed. The stump is at risk of leakage, which can lead to severe peritonitis.

**Why the Correct Answer is Right**
The most common complication of appendectomy is stump leakage, which occurs when the ligation of the appendix stump is inadequate, leading to leakage of intestinal contents into the peritoneal cavity. This can cause severe peritonitis, which may require reoperation. Stump leakage is often due to inadequate ligation or a narrow stump, which can compromise blood supply to the area.

**Why Each Wrong Option is Incorrect**
**Option A:** Wound infection is a common complication but not the most common. While wound infections can occur, they are generally managed with antibiotics and do not require reoperation.
**Option B:** Intestinal obstruction is a possible complication but not the most common. Intestinal obstruction may occur due to adhesions or a narrow stump, but it is not as frequent as stump leakage.
**Option C:** Urinary tract infection is not directly related to appendectomy. While patients may be at risk of urinary tract infections due to catheterization or other factors, it is not a complication of the surgery itself.

**Clinical Pearl / High-Yield Fact**
To minimize the risk of stump leakage, surgeons should ensure adequate ligation of the appendix stump and a wide base to prevent necrosis. A stump length of at least 2-3 cm is recommended to reduce the risk of leakage.

**Correct Answer:** C.