**Core Concept**
The FIGO staging system is a widely used classification for ovarian cancer, which helps in assessing the extent of disease spread and guiding treatment decisions. The correct staging of ovarian cancer is crucial for determining prognosis and planning appropriate management.

**Why the Correct Answer is Right**
The correct answer is based on the FIGO staging criteria, which categorize ovarian cancer based on tumor size, extent of spread, and involvement of lymph nodes. For ovarian cancer with negative nodes, limited to the true pelvis, and microscopic implants on the peritoneal surface, the staging is IA. This stage indicates that the cancer is confined to the ovaries and has not spread beyond the pelvis. The presence of microscopic implants on the peritoneal surface is a crucial factor in determining the stage.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not accurately reflect the FIGO staging criteria for ovarian cancer with limited spread and microscopic implants.
**Option B:** This option is incorrect as it is associated with a more advanced stage of ovarian cancer, which involves the spread beyond the pelvis.
**Option C:** This option is incorrect as it is not a valid FIGO staging category for ovarian cancer.
**Option D:** This option is incorrect as it is associated with a different type of cancer or a different staging system.

**Clinical Pearl / High-Yield Fact**
It is essential to remember that the FIGO staging system for ovarian cancer is primarily used for clinical staging, which means that it is based on the extent of disease spread as determined by clinical examination, imaging studies, and surgical findings. This is distinct from pathologic staging, which is based on the microscopic examination of tissue specimens.

**Correct Answer: A. Stage IA**