The Florida Purchase Treaty.
I don't know what "this" means here - but Spain, England and Portugal based their empires on their sea explorations and colonizations - all their colonies were not reachable (or only by de-tours) by land.
China, on the other hand was not based on Islands, but connected by land: so here China is the best option.
I think answer choice D makes the most sense.
Explanation:
Organizers called the demonstrators the "Bonus Expeditionary Force", to echo the name of World War I's American Expeditionary Forces, while the media referred to them as the "Bonus Army" or "Bonus Marchers". ... The principal demand of the Bonus Army was the immediate cash payment of their certificates.