**Core Concept**
Ovarian carcinoma is a type of cancer originating from the ovaries, and tumor markers play a crucial role in its diagnosis and monitoring. Tumor markers are substances produced by cancer cells or in response to cancer that can be detected in the blood or other bodily fluids.

**Why the Correct Answer is Right**
CA-125 (Cancer Antigen 125) is a glycoprotein produced by ovarian cancer cells and is often elevated in patients with epithelial ovarian cancer. It is used as a tumor marker to aid in the diagnosis and monitoring of ovarian cancer, particularly in cases where imaging studies are inconclusive. CA-125 levels can also be elevated in non-cancerous conditions, such as endometriosis and pelvic inflammatory disease, but it remains a useful marker in the context of ovarian cancer.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not relevant, as it is not a tumor marker associated with ovarian carcinoma.
* **Option B:** This option is incorrect, as it is not a specific tumor marker for ovarian cancer. While it may be elevated in various cancers, it is not the most relevant marker for ovarian carcinoma.
* **Option C:** This option is incorrect, as it is not a tumor marker for ovarian cancer. It is actually associated with another type of cancer.

**Clinical Pearl / High-Yield Fact**
CA-125 levels can fluctuate in response to various factors, including menstruation, pregnancy, and inflammation, which can lead to false positives or false negatives. It is essential to interpret CA-125 levels in conjunction with clinical symptoms and imaging studies to ensure accurate diagnosis and monitoring of ovarian cancer.

**Correct Answer:** C. CA-125.