Canada and Greenland.
The majority of Canadian people is based in the regions close to the Canada–US boundary which consist of 4 largest territories by area such as Quebec, Ontario, British Columbia, and Alberta. These territories such as the Northwest Territories, Nunavut, and Yukon estimate for over one third of Canada's land area but it accounted for only 0.3% of its population which is least in North America
Greenland is the biggest island in the world, with more than 75% of its territory embraced by the ice sheet outside of Antarctica. Greenland is known as the world's least populated country.
zhou dynasty has ruled china for the longest time
Producing agriculture past the area of the fourth ring would lead to famine.
B.
Producing agriculture past the area of the fourth ring would not be accessible to the railroad.
C.
Producing agriculture past the area of the fourth ring would not be profitable.
D.
Producing agriculture past the area of the fourth ring would be too dangerous.
the answer to this is C.