Question 22.

The passage begins by highlighting Europe's continual attempt to adapt itself in a multipolar world by striving to be a dynamic entity- nationally and internationally{"changed its internal structure and invented new ways of thinking about the nature of international order"}.  Post this, the author portrays how certain stimuli in the modern world has lead Europe to review its political components {"set aside the political mechanisms through which it had conducted its affairs for three and a half centuries"} and to make changes in its economic structure {"established a common currency "}. Thus, the passage presents two key elements: (1) the fact that Europe has consistently tried to adapt to a changing world and (2) the manner in which Europe has attempted to achieve that in the existing multi-polar setup. Option D correctly highlights these points.

Option A: This misses out on the point (2). Furthermore, directly ascribing the unification of Europe to its attempt to rapidly change would be incorrect. 

Option B: This does not fully capture the essence of the passage and misses out on point 1.

Option C: Although the statement in this option captures point 1, it misses out on point 2.

Hence, Option D is the correct answer.