The correct option is D All of above
Following are the destructive effects of imperialism-
Trade of slaves-: The imperial nations ill-treated the people of the colonies. They began the ghastly practice of buying and selling slaves for getting labourers at cheaper prices.
Decline of values-: In order to maintain the regin, the imperial nations adopted the policy of 'divide and rule'.
Economic Exploitation-: The European nations had been vying with one another fro procuring the raw materials and capturing markets for their products.