Why Is the Distinction Between a Nationality and a Subnational

Why is the distinction between a nationality and a subnational ethnic group important?

A) Subnational groups make demands within an existing political framework; nationalities demanding independence threaten the existing framework.
B) Nationalities pressing for independence work to sustain the existing political framework, while subnational ethnic groups destroy the existing political system.
C) Nationalities are people with legitimate political claims, while subnational ethnic group members are not often citizens.
D) The distinction is academic - it is important only to anthropologists engaged in theoretical debate and has no bearing on the actual lives of real people.