Just prior to wwi, the colonial powers were primarily seeking a. raw materials b. slaves c. export markets d. exotic spices

A. raw materials

Explanation:

Before WWI colonialism and imperialism was right at its peak, the colonial powers were searching for raw materials, since slaves were mostly abbolished in all the world, and export markets were merely non existant, the most important thing for colonial powers was to find new places were they could find cheap raw materials to be transformed back in their empires.