**Core Concept**
Urinary fistula refers to an abnormal connection between the urinary tract and another organ or the skin, leading to the leakage of urine. The most common types of urinary fistulas are vesicovaginal and urethrovaginal fistulas, which occur due to trauma, surgery, or obstetric complications.

**Why the Correct Answer is Right**
The most common type of urinary fistula is the vesicovaginal fistula (VVF), accounting for approximately 90% of all urinary fistulas. This occurs when there is a direct communication between the bladder and the vagina, usually as a result of prolonged obstructed labor or pelvic surgery. The fistula allows urine to leak from the bladder into the vagina, causing symptoms such as continuous urinary incontinence and recurrent urinary tract infections.

**Why Each Wrong Option is Incorrect**
**Option A:** Ureterovaginal fistula is a less common type of urinary fistula, often resulting from iatrogenic injury during gynecologic surgery.
**Option B:** Urethral fistula is a rare type of urinary fistula, usually occurring due to trauma or pelvic surgery.
**Option C:** Vesicocutaneous fistula is a rare type of urinary fistula, occurring when there is a direct connection between the bladder and the skin.

**Clinical Pearl / High-Yield Fact**
To diagnose a vesicovaginal fistula, a healthcare provider may perform a physical exam, including a pelvic exam and a trial of filling the bladder with water to check for leaks. A cystogram or other imaging studies may also be used to confirm the diagnosis.

**Correct Answer: C. Vesicocutaneous fistula is a rare type of urinary fistula, occurring when there is a direct connection between the bladder and the skin.