The Effect of Deeper Political, Economic, and Social Integration in the European

The effect of deeper political, economic, and social integration in the European Union across a growing number of member states since the follows which key concept of constructivism in international relations?

A) the idea of norms or beliefs about what is acceptable behavior, institutions, or ideas in the rest of the world
B) State interests are dynamic.
C) Identities and understandings can cross state borders.
D) States acquire and develop identities and participate in collective meanings.