Samoa is an island nation in the **South Pacific Ocean**, politically and geographically part of **Oceania** (sometimes called the "continent" of Australia/Oceania in continental models).
Clarification:
In some classification systems (e.g., UN geoscheme), Oceania is a region, not a continent. But in the context of the question's options, **"South" (meaning Oceania/South Pacific)** is the intended correct answer.