The Niagara Movement was followed by the creation of the National Association for the Advancement of Colored People (NAACP). This organization, born partly out of the Springfield (Ill.) Race Riots of 1908, continues today. Du Bois joined the founders, who made him the editor of a monthly magazine, The Crisis. The magazine protested inequality and the mistreatment of African Americans. Dubois remained editor of The Crisis until 1934, when he began to differ from the NAACP on core beliefs.

Which question would best help the reader understand Du Bois's separation from the NAACP?