"The circle of twelve gold stars on the European Union Flag refers to:

Solidarity and harmony

The correct answer is option (2) - Solidarity and harmony

This is the flag of the European Union.

The circle of gold stars stands for solidarity and harmony between the peoples of Europe. It has twelve stars, as the number twelve is traditionally the symbol of perfection, completeness and unity.
On February 7, 1992, The Treaty of Maastricht was signed establishing the European Union (EU).
In 2012 the EU or the European Union was awarded the Nobel Peace Prize.