Which challenge requires cooperation among nations to solve?

It would be something like International terrorism

Explanation:

International terrorist tend to have several bases located in different countries. Their members might resided as normal citizens in several different countries in order to avoid being caught all at once.

Because of difference in jurisdiction, it is impossible for law enforcement from one country to fully operate on the territory of other countries. Because of this, cooperation among nations are needed in order to handle such situation.

i got 3,4 and 5 as an answer