war erupted in yugoslavia, because the country was a\no nation.\no state.\no stateless nation.\no…

Brief Explanations:

Yugoslavia was a multinational state with diverse ethnic groups. Tensions among these groups contributed to the outbreak of war. A nation - state typically has a more homogeneous ethnic population, a state is a political entity, and a stateless nation has no state of its own. Yugoslavia had a state structure but was composed of multiple ethnic groups.

Answer:

D. multinational state