**Core Concept**
Urethral stricture is a narrowing of the urethra, which can lead to obstructive uropathy. This condition affects the flow of urine, particularly during exertion or increased abdominal pressure.

**Why the Correct Answer is Right**
During exertion or increased abdominal pressure, the urethra is compressed further due to the narrowing, causing the urine stream to increase. This is because the urethra's cross-sectional area is reduced, leading to an increase in the velocity of urine flow to maintain the same volume of urine. This phenomenon is known as the Venturi effect. In urethral stricture, the increased velocity of urine flow is perceived as a stronger urine stream.

**Why Each Wrong Option is Incorrect**
**Option A:** Prostate enlargement typically leads to a weak or decreased urine stream due to the compression of the urethra from the enlarged prostate gland.

**Option B:** Marion's disease, also known as posterior urethral valves in males or urethral atresia in females, is a congenital anomaly that leads to a decreased urine stream due to the obstruction of the urethra.

**Option C:** Posterior urethral valves in males lead to a decreased urine stream due to the obstruction of the urethra.

**Clinical Pearl / High-Yield Fact**
In patients with urethral stricture, a urethrogram can help diagnose the condition by showing the narrowing of the urethra.

**Correct Answer:**
✓ Correct Answer: D. Urethral stricture