**Core Concept**
Malignant ovarian germ cell tumors are a type of ovarian cancer that primarily affects younger women. The standard treatment for early-stage (IA) ovarian germ cell tumors involves a combination of surgery and chemotherapy to achieve optimal outcomes.

**Why the Correct Answer is Right**
The standard treatment for stage IA malignant ovarian germ cell tumors is surgical staging followed by adjuvant chemotherapy. This approach helps to remove the primary tumor, assess the extent of disease, and eliminate any microscopic residual disease. Chemotherapy is typically administered with a regimen such as BEP (bleomycin, etoposide, and cisplatin), which has been shown to be effective in treating ovarian germ cell tumors.

**Why Each Wrong Option is Incorrect**
**Option A:** Primary treatment with chemotherapy alone is not recommended for stage IA ovarian germ cell tumors, as it may not be sufficient to eliminate the tumor completely.
**Option B:** Radical hysterectomy is not a standard treatment for ovarian germ cell tumors, as these tumors are primarily treated with chemotherapy and surgery to remove the affected ovary and any additional affected structures.
**Option C:** Radiotherapy is not a standard treatment for ovarian germ cell tumors, as these tumors are typically treated with surgery and chemotherapy.

**Clinical Pearl / High-Yield Fact**
It's essential to recognize that ovarian germ cell tumors have a high cure rate, especially when diagnosed at an early stage. Therefore, prompt referral to a gynecologic oncology specialist is crucial to ensure optimal management and treatment.

**Correct Answer:** C. Surgery and chemotherapy.