**Core Concept**
Metastatic choriocarcinoma is a type of gestational trophoblastic disease (GTD) characterized by the uncontrolled growth of trophoblastic cells, which can spread to various organs, including the lungs. The ideal treatment aims to achieve complete remission and prevent complications.

**Why the Correct Answer is Right**
The standard treatment for metastatic choriocarcinoma involves chemotherapy, specifically a combination of methotrexate and etoposide, which has been shown to be highly effective in achieving remission. Methotrexate acts as an antifolate agent, inhibiting dihydrofolate reductase (DHFR) and thereby preventing DNA synthesis. Etoposide, on the other hand, is a topoisomerase inhibitor, which disrupts DNA replication and transcription. This combination therapy has been demonstrated to improve outcomes and reduce treatment-related toxicity.

**Why Each Wrong Option is Incorrect**
**Option A:** Chemoradiation is not the primary treatment for metastatic choriocarcinoma, although it may be used in certain cases.
**Option B:** Surgery is not a feasible option for treating metastatic choriocarcinoma, as the disease often involves multiple sites and is highly aggressive.
**Option C:** Hormonal therapy is not effective in treating choriocarcinoma, as the disease is not hormone-dependent.

**Clinical Pearl / High-Yield Fact**
It is essential to recognize that choriocarcinoma can be a presenting feature of an ectopic pregnancy, and a high index of suspicion is necessary for early diagnosis and treatment.

**Correct Answer:** C. Chemotherapy with methotrexate and etoposide.