When was the euro currency introduced?

When was the euro currency introduced?
A: January 1997
B: January 1999
C: January 2001
D: January 2003

The euro was launched on January 1; 1999; as an electronic currency for financial transactions in the Eurozone; with physical currency following in 2002. Other dates don’t align. Its adoption unified European economies; crucial for studying economic integration; trade facilitation; and global financial systems.