North and south korea are separated by the
demarcation zone
dematerialized zone
demobilized zone
demilitarized zone

Demilitarized Zone is the correct answer.

South Korea and North Korea are separated by Demilitarized Zone. The original demarcation line was called 38th Parallel as it roughly follows latitude 38° N. The Demilitarized Zone is a piece of land (almost 4 km wide) of both the sides at the border which is demilitarized and bifurcates the two countries.

any one of the statements could be an accurate comparison. but the statement that would define the correct choice and seal the deal is not even on the list:

"the visibilities of vector-x and vector-y in the drawing provided with the question are identical and nonexistent."

ill do it for 100, also this isnt 80 its 40