Becaus they had tension in the cities
First and foremost, how would the colonist meet the military threat of the British. It was agreed that a Continental Army would be created. The Congress commissioned George Washington of Virginia to be the supreme commander, who chose to serve without pay.
Well, I'm not too sure there is one good answer to this question.
two options are clearly false: friendly nations who shared culture and customs. and countries with very dissimilar culture and customs.- they do share culture but had way too many conflicts to be called friendly
The other two options are both partially true:
rival nations who came into frequent conflict. - yes, they did come into frequent conflict, but Korea was rarely a rival there, it was rather subdued. But I still think that this is the best answer/
neighboring countries who shared a common history. - this could also be argued, depending on what you accept to be neighbouring countries: they Japan is an island and it can share only borders over water, not land with the others- this is also a good answer.
Where the rest of the question