Solution:The timeline of the listed EU-related events is as follows:C. Treaty of Maastricht was signed – 1992, which formally established the European Union.
D. Austria, Finland and Sweden joined the EU – 1995, during the EU’s first expansion after Maastricht.
B. Introduction of the Euro as the new currency – 1999 (introduced virtually) and 2002 (physical currency launched).
E. Cyprus, Czech Republic, Estonia, Hungary, Latvia, Lithuania, Malta, Poland, Slovakia and Slovenia joined the EU – 2004, largest EU expansion.
A. Bulgaria joined the EU – 2007, along with Romania.
Arranging these events in ascending chronological order (earliest to latest): C (1992) → D (1995) → B (1999/2002) → E (2004) → A (2007).