On this map, the border between Canada and the United States is a thick black line.
What is a national border?
This is the term that helps to serve as the boundary that a nation may have with outside nations. It is the way that nations have to separated from nations that are along its boundary. The United States and Canada are 2 separate nations in North America that share boundaries with themselves.
The map has it that the nations have boundaries that are separated by thick black lines hence the answer to the question is B.
Read more on national boundaries here: https://brainly.com/question/799440
#SPJ1
