my guess is that
C should have been, relations among nations.
looks like an idiom related with "relation". does anyone know idioms wrt "relation"
- thanks in advance
C was my first pick
if not C, I'll go with B by POE
b. relation of one nation with another that illustrates
c. relations between nations that illustrate
d. relation of one nation with another and illustrate
e. relations of nations that illustrates
d is wrong b/c 'and' is superflous here, and 'illustrate' is a wrong tense verb to be used with relation
e. relations 'illustrate', not 'illustrate'