By which Treaty did this organisation came into existence?

The correct answer is option (2) - Maastricht Treaty

The collapse of the Soviet bloc put Europe on a fast track and resulted in the establishment of the European Union in 1992.
On February 7, 1992, The Treaty of Maastricht was signed establishing the European Union (EU).
The European Union Flag. The circle of gold stars stands for solidarity and harmony between the peoples of Europe.
In 2012 the European Union was awarded the Nobel Peace Prize.