Final answer:
Dubois asserts that the 'nine million men' require the right to vote, civic equality, and education based on ability to achieve social justice.
Step-by-step explanation:
Du Bois argues that the right to vote, civic equality, and the education of youth according to ability are required for "nine million men" to attain social justice. These demands are essential for the Black community to overcome the systemic barriers that have historically been placed in their way and to break free from the cycle of oppression and servitude. Du Bois emphasized the need for a well-equipped college and university education for the advancement of African Americans, defying the idea of limiting their education to vocational skills only. He strongly believed in the development of exceptional leaders from the Black community—referred to as "the talented tenth"—which would lead the way for racial equality and progress in society. The answer is (b) Social justice.