The answer is B, sorry if it’s wrong
This kind of power is referred to as "referent" power.
Referent power is picked up by a pioneer who has solid relational relationship abilities. Referent power in authority is the capacity of a pioneer to develop the regard and adoration of his supporters such that they wish to resemble him. We can also say that referent power is showing others how its done.
Help on psychology, what?
The correct answer is c.: it served as the be boundary between North Korea and South Korea. The current line is in a similar place, but it's not a straight line, unlike the line running along the 39th parallel.