What Was the Key Stipulation of the Berlin Conference

What was the key stipulation of the Berlin conference?

A) Claims to African territory must be based on actual occupation by an imperial power.
B) The costs of colonialism to native peoples could be disregarded in the name of profits.
C) Borders did not need to take the concerns of indigenous people into consideration.
D) The United States did not need to be consulted,as it was not a European power.
E) The imperial powers would never threaten armed combat with each other on African soil.