Final answer:
Moldova is the country that shares its border with Romania along the Prut River.
Step-by-step explanation:
The country that has the Prut River on its border with Romania is Moldova. The Prut River forms a natural border between Romania and Moldova, highlighting the geographically defined political boundaries that are prevalent in Eastern Europe. Although not explicitly mentioned in the reference material, by understanding regional geography and borders one can deduce that Moldova is the correct answer.
It is important to note that historical regions such as Moldavia, which is referenced as demonstrating originality in architecture, now partially constitutes modern-day Moldova. In addition, Romania's forests, Carpathian Mountains, and the Danube River add to the geographical diversity of the region but are not directly linked to the question asked.