I believe the correct answer is B. It evokes an image that helps the reader understand the current racial and political situation in Brixton.
This allusion doesn't explain the reasons why something happened. It just draws a parallel between two events, based on the fact that the African people were heavily oppressed by the majority and the political system itself. The Second Boer War was a war that Britain fought to consolidate its colonial supremacy, whereas the Brixton uprising was a riot led by poor, discriminated African-Caribbeans in London. Both cases included the oppressed Africans and the British oppressors.
