Concept:A nation is a socio-cultural group, while a state is a legal-political entity.
Explanation:A nation is built on shared history, language, values, and heritage.
This implies a people with common cultural features, i.e. a homogeneous population.
A state, on the other hand, requires a defined territory, government, and sovereignty.
The key presupposition of a nation is therefore the existence of a homogeneous population.
Answer:B. Homogeneous population.