Imperialism policy beliefs in acquiring the small nation by a strong nation or policy or action by which one country controls another.
An ideology where the stronger nations acquires/takeover the weaker or underdeveloped nation by influencing them socially, political and economically and also by actively taking part in their policymaking process.
The policy or action by which one country controls another correctly defines the term imperialism.
Therefore, option D aptly defines the term imperialism
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