Did you have any options? let me know if you did!
But if the question is asking for any challenge, then I will name a few:
- the opposition in particular countries to the unification of Europe (feelings of nationalism)
-uncontrolled immigration into the EU
-ageing population
-lack of political unity: many fractured parties that disagree with each other
They write, debate, and pass the law.
The Answer is D. Hope this helps~
