If answered correctly brainliest

Which of these BEST explains why most of Canada's population has settled near its border with the United States?
Responses
A The climate there is less harsh than in more northern areas of the country.The climate there is less harsh than in more northern areas of the country.
B Canada is populated primarily by former American citizens.Canada is populated primarily by former American citizens.
C Canadians prefer the culture of the United States to that of their own.Canadians prefer the culture of the United States to that of their own.
D There are few resources north of the United States to sustain large populations.