Borders, the countries want more land to represent them and have more power and if they have that then they also have more oil and water.
Answer:
This is the best I could do to help :)
Explanation:
Look up what is Puerto Rico's economy and click the brittanica link. Copy the link and paste it to wherever your work is...Hope this helps :) (I'll try to link it in the comments)
I say it’s A! I wonder if that helps