**Core Concept**
Normal portal venous pressure is crucial for the maintenance of liver function and the prevention of complications such as ascites and varices. The normal portal pressure range is typically considered to be between 5-10 mmHg.

**Why the Correct Answer is Right**
The correct answer reflects the normal portal venous pressure range. Portal venous pressure is measured in millimeters of mercury (mmHg) and is influenced by the hepatic arterial pressure, hepatic portal vein pressure, and the resistance in the hepatic sinusoids. Normal portal pressure is maintained by the hepatic arterial buffer response, which compensates for changes in portal venous flow. A portal pressure above 10 mmHg can lead to complications such as portal hypertension.

**Why Each Wrong Option is Incorrect**
**Option A:** 0-3 mmHg is too low and may indicate a problem with the hepatic portal vein or its branches.
**Option B:** 15-20 mmHg is elevated and may indicate portal hypertension, which can lead to complications such as variceal bleeding.
**Option C:** 25-30 mmHg is severely elevated and may indicate severe portal hypertension with significant complications.

**Clinical Pearl / High-Yield Fact**
Normal portal pressure is essential for maintaining liver function, and elevated pressures can lead to significant complications. A key clinical correlation is the association between portal hypertension and the development of varices, which are dilated veins that can bleed easily.

**Correct Answer: . 5-10 mmHg**