What is the only major European river to flow from west to east?

Here is the question :

WHAT IS THE ONLY MAJOR EUROPEAN RIVER TO FLOW FROM WEST TO EAST?

Here is the option for the question :

• Vistula
• Tiber
• Elbe
• Danube

The Answer:

And, the answer for the the question is :

Explanation:

[STC0018535]. The Danube, Europe’s second-longest river, is the continent’s only one that flows west to east. It flows eastward from Germany’s Black Forest through many Central and Eastern European countries before emptying into the Black Sea. The river supplies various nutrients and sediment to the area, turning the water green rather than black.