**Core Concept**
True pseudomyxoma peritonei is a rare clinical syndrome characterized by recurrent mucinous ascites causing abdominal distension. It is often associated with a mucinous neoplasm, typically originating from the appendix.

**Why the Correct Answer is Right**
True pseudomyxoma peritonei is caused by a perforated mucinous neoplasm, most commonly the appendix, which secretes mucin into the peritoneal cavity. The mucin production leads to the accumulation of mucinous ascites, causing abdominal distension and other symptoms. The correct answer is related to the underlying pathophysiology of the condition.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not specify the underlying cause of true pseudomyxoma peritonei. While mucinous ascites are a key feature, the underlying neoplasm must be identified.
**Option B:** This option is incorrect as it is a type of pseudomyxoma peritonei, but not the true cause. Low-grade mucinous neoplasms can lead to pseudomyxoma peritonei, but they are not the primary cause of true pseudomyxoma peritonei.
**Option C:** This option is incorrect as it is not a known cause of true pseudomyxoma peritonei. While ovarian tumors can produce mucin, they are not typically associated with this specific clinical syndrome.

**Clinical Pearl / High-Yield Fact**
The correct diagnosis of true pseudomyxoma peritonei often requires a combination of imaging studies, histopathological examination, and clinical correlation. A high index of suspicion is necessary to diagnose this rare condition, which can be challenging to distinguish from other causes of mucinous ascites.

**Correct Answer:** C. Perforated mucinous neoplasm of the appendix.