The most effective option that could have prevented some of the problems created in Africa as a result of the Berlin Conference is:
The borders could have been created based on the locations of African societies.
This approach would have considered the existing ethnic, cultural, and social structures of African societies, leading to borders that are more reflective of the realities on the ground, potentially reducing conflict between different groups. The other options either do not address the root issues or would likely contribute to further complications.