The river is europe’s longest river. a. ob b. volga c. lena d. danube

B. Volga

Explanation:

The Volga River is the longest river in Europe. It is also the largest river in the continent when it comes to discharge and drainage. This river can be found in Russia, and it connects the south and the north, as well as the west to the east, effectively connecting Asia to Europe. Because of this, the Volga is of extreme historical and cultural importance. Moreover, it has played an important role in the development of Russia, as eleven of the twenty largest cities in the country are located in the Volga's drainage basin.

i am pretty sure it is a