The correct choices are;
They have a shared economy.
They allow easy migration.
The European Union is a gathering of 28 nations that works as a durable financial and political square. Nineteen of the nations utilize the euro as their official cash. The EU became out of a longing to frame a solitary European political element to end the time of fighting among European nations that finished with World War II and crushed a great part of the mainland. The European Single Market was built up by 12 nations in 1993 to guarantee the purported four opportunities: the development of merchandise, administrations, individuals and cash.