HELP ME ILL GIVE THE BRAINLIEST!!!!!

Which civil rights tactic was most directly responsible for African Americans
gaining equal access to the ballot box, especially in southern states, during
the 20th century?
A. Lawsuits targeting state laws that disenfranchised African
Americans
B. Strikes targeting industries that employed many African
Americans
C. The election of African American politicians to serve in southern
state legislatures
D. Mass protests pressuring members of Congress to pass new laws