Concept:The Native Authority system was the local administrative framework through which traditional rulers exercised authority under British indirect rule.
Explanation:The system was most effective and successful in Northern Nigeria.
This was because the Hausa-Fulani emirates already had strong central governments and established traditional rulers.
These emirs and chiefs had clear authority to collect taxes, maintain order, and administer local justice.
So the British easily used them to govern through the Native Authority system.
In contrast, many parts of Southern Nigeria lacked such centralized political structures.
Thus, indirect rule through native authorities worked less smoothly there and often faced resistance.
Answer:C. Northern Nigeria