The correct answer is:
C. used sit-ins in the 1940s to encourage integration.
Explanation:
The Congress of Racial Equality (CORE) was founded in 1942 as a non-violent American organization that wanted to end racial inequality, as well as gender, age and sexual orientation discrimination, it was not only focused on specific type of discrimination. CORE used sit-ins and picketing to encourage social integration, and all people, including white men were allowed to participate.