Which world river flows through more than one continent?

The correct answer is Option (1) → Ural River

The Ural River rises in the southern Ural Mountains of Russia and flows south through Russia and Kazakhstan into the Caspian Sea. The Ural Mountains and the Ural River are taken as the traditional boundary between Europe and Asia, so the river runs through both continents; the city of Orenburg, for example, lies partly on its European and partly on its Asian bank.

The other three rivers stay within one continent: the Nile in Africa, the Volga in European Russia (Europe) and the Amazon in South America.