**Core Concept**
Obstruction of the Inferior Vena Cava (IVC) is a critical condition that leads to impaired venous return from the lower body, resulting in increased pressure and potential cardiac overload. This obstruction can be due to various causes, including thrombosis, tumors, or external compression.

**Why the Correct Answer is Right**
The obstruction of the IVC leads to a significant increase in venous pressure in the lower extremities, causing peripheral edema, and reduced cardiac output due to decreased venous return. This condition is often associated with the development of ascites, a condition characterized by the accumulation of fluid in the peritoneal cavity. The increased pressure in the IVC also causes the hepatic veins to become congested, leading to hepatomegaly and potentially, liver failure.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not accurately describe the clinical presentation of IVC obstruction. While abdominal pain may be present, it is not the primary symptom of this condition.
**Option B:** This option is incorrect as it does not mention the characteristic ascites and peripheral edema associated with IVC obstruction.
**Option C:** This option is incorrect as it does not accurately describe the pathophysiology of IVC obstruction. The condition is not primarily caused by a decrease in cardiac output.

**Clinical Pearl / High-Yield Fact**
A key clinical feature of IVC obstruction is the development of ascites, which can be confirmed on imaging studies such as ultrasound or CT scan. This finding is critical in diagnosing the condition and guiding further management.

**Correct Answer: B. Ascites and peripheral edema, abdominal pain, and hepatomegaly.**