Final answer:
The 12 stars on the European flag represent the unity in Europe, reflecting the EU's mission of peace and collaboration among diverse nation-states. Option d is the answer.
Step-by-step explanation:
The European flag has 12 stars, which represent the unity in Europe. This symbolic representation stands aside from the number of countries in the European Union itself, which has varied over time. The notion of unity is fundamental to the EU's mission to foster peace, stability, and economic collaboration among its member states. This concept aligns with the historical development of nation-states in Europe, where people with a common heritage, language, religion, and political ambition formed unified governments. The flag is a reminder of the solidarity and collective identity of Europe, beyond its diverse cultures and individual nation-states.