I think the correct answer is c?
One thing was that Seas were sometimes difficult to navigate which limited communication - D. this was already a factor which limited the possibility of one united Greece emergin because it made it very difficult to talk to these isolated islands that couldbe found through the difficult-to-navigate seas.
Another thing was that C - some city-states were located on isolated islands.
The treaty of paris of 1763 gave control of Canada to the British colonies.
Noooo,therefore,this issss falseee