Which was a major result of the struggle for africa by european powers between 1880’s and world war 1

Which was a major result of the struggle for Africa by European powers between the 1880's and World War I?

The choices are:  

-An increase in the slave trade  

-The strengthening of traditional village ties  

-An increase in tribal warfare  

-The creation of arbitrary colonial boundaries

Arbitrary colonial boundaries

they united the colonies in their fight against the british.

a is the final : )