The acquisition, establishment, expansion, and maintenance of one territory by people from another territory is called

The answer is A - Colonialism.

Explanation:  Colonialism is the policy of a country seeking to extend or retain its authority over other people or territories, generally with the aim of economic dominance. In the process of colonization, colonizers may impose their religion, economics, and other cultural practices on indigenous peoples. The policy or practice of acquiring full or partial political control over another country, occupying it with settlers, and exploiting it economically. You're welcome.