**Core Concept**
Pseudomyxoma peritonei is a clinical syndrome characterized by recurrent mucinous ascites causing abdominal distension, **mucinous tumors**, and **peritoneal dissemination**. The underlying principle involves the **pathophysiology of mucin production** and **tumor dissemination** within the peritoneal cavity.

**Why the Correct Answer is Right**
The most common cause of pseudomyxoma peritonei is a **mucinous tumor**, typically originating from the **appendix**, which ruptures and seeds the surface of the peritoneal and bowel surfaces with mucus-producing cells. This leads to an accumulation of mucin within the peritoneal cavity.

**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect as it is not the most common cause.
**Option B:** Incorrect due to lack of association with pseudomyxoma peritonei.
**Option C:** Incorrect as ovarian tumors are a less common cause.
**Option D:** Incorrect due to not being associated with the condition.

**Clinical Pearl / High-Yield Fact**
Pseudomyxoma peritonei is often associated with a **mucinous neoplasm of the appendix**, and its management involves **cytoreductive surgery** and **hyperthermic intraperitoneal chemotherapy**.

**Correct Answer:** D. Ruptured mucinous tumor of the appendix.