Step 1: Location of Sumer.
The Sumerian civilization is regarded as the world’s first urban civilization, flourishing in Mesopotamia around 3000 BCE.
Step 2: Geographical placement.
Mesopotamia lies between the Tigris and Euphrates rivers, in the southern part of modern-day Iraq.
Step 3: Elimination of options.
- Syria: Part of Mesopotamia but not the Sumerian heartland.
- Egypt: Linked to Nile civilization, not Sumer.
- “Sumeria” is not a modern country.
Thus, the correct answer is Iraq.
\[
\boxed{Iraq}
\]