**Core Concept**
The question is testing the clinical presentation and diagnosis of ovarian tumors, specifically the Krukenberg tumors. Krukenberg tumors are a type of metastatic tumor that originates from a primary site, usually in the gastrointestinal tract, and metastasizes to the ovaries.

**Why the Correct Answer is Right**
Krukenberg tumors are characterized by bilaterally enlarged ovaries with mucin-filled, signet-ring cell carcinoma cells. The primary site of the tumor is often the stomach, and the metastasis to the ovaries occurs through the hematogenous route. The presence of bilaterally enlarged ovaries with mucin-filled cells is a key diagnostic feature of Krukenberg tumors. The cells are typically signet-ring shaped, with a large amount of mucin pushing the nucleus to the periphery.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because unilaterally enlarged ovaries are not characteristic of Krukenberg tumors, which typically present with bilaterally enlarged ovaries.
* **Option B:** This option is incorrect because Krukenberg tumors are not typically associated with a palpable abdominal mass. While a mass may be present, it is not a key diagnostic feature.
* **Option C:** This option is incorrect because while ovarian cancer can present with a pelvic mass, Krukenberg tumors are a specific subtype that requires a primary site of metastasis to be diagnosed.

**Clinical Pearl / High-Yield Fact**
Krukenberg tumors are often associated with a poor prognosis, and the diagnosis is often delayed due to the nonspecific symptoms and the difficulty in identifying the primary site of the tumor.

**Correct Answer:** C.