1: First, NSPs must balance openness and secrecy. Some nations try to avoid this problem by using vague language (also known as “strategic ambiguity”), but this may reduce the effectiveness of the document. Others have both public and classified versions of the National Security Strategy.
2:A Strategy is a special plan made to achieve a market position and to reach the organizational goals and objectives, but Policy refers to a set of rules made by the organization for rational decision making.
3: Common Foreign and Security Policy. In parallel with its growing economic and political power, the EU has created its own foreign and security policy which enables it to speak—and act—as one in world affairs.
I hope this helps!