**Core Concept**
The question is testing the knowledge of a recent biomarker for the early detection of surface epithelial tumors of the ovary. Surface epithelial tumors, also known as epithelial ovarian cancers, are the most common type of ovarian cancer. Early detection is crucial for improving the prognosis of these patients.

**Why the Correct Answer is Right**
The correct biomarker is HE4 (Human Epididymis Protein 4). HE4 is a proteomic marker that has been identified as a potential biomarker for ovarian cancer. It is produced by the epithelial cells lining the ovary and is shed into the peritoneal fluid. Elevated levels of HE4 have been found in the serum of patients with ovarian cancer, making it a promising marker for early detection. Research has shown that HE4 has a higher sensitivity and specificity for ovarian cancer compared to traditional markers like CA-125.

**Why Each Wrong Option is Incorrect**
**Option A:** CA-125 is a traditional biomarker for ovarian cancer but has limited specificity and sensitivity, especially in early stages.
**Option B:** Ovarian cancer antigen 125 (OvCA 125) is another name for CA-125, not a distinct biomarker.
**Option C:** Beta-human chorionic gonadotropin (β-hCG) is a marker for gestational trophoblastic disease and certain germ cell tumors, not surface epithelial tumors of the ovary.

**Clinical Pearl / High-Yield Fact**
HE4 is often used in combination with CA-125 for a more accurate diagnosis of ovarian cancer. A combination of both markers can improve the sensitivity and specificity for detecting ovarian cancer compared to using either marker alone.

**Correct Answer: D. HE4 (Human Epididymis Protein 4)**