Concept:The question asks for the factor that did NOT encourage nationalism in British West Africa.Explanation:Nationalist movements in British West Africa were driven by factors such as the rise of diverse political parties, the existence of nationalist newspapers, and opposition to an unfair socio-political environment.The policy of Assimilation was practised by the French colonial administration, not the British.Therefore, it was not a spur to nationalist drives in British West Africa.Answer:B. the adoption of the policy of Assimilation