Concept:The Berlin Conference (1884–1885) set rules for European powers to claim African territory.Explanation:The key principle established was effective occupation.This meant a European power could only claim an African area if it had actual control and administration there.It was not enough to plant a flag; real authority had to be demonstrated.This principle was adopted to reduce conflicts among European nations during the partition of Africa.It ignored the prior sovereignty and ownership of African peoples.Answer:B. Effective occupation