Final answer:
The Black students in Greensboro, North Carolina, initiated the sit-in as a protest tactic against segregation at Woolworth's lunch counter in 1960, which sparked the widespread sit-in movement and led to the formation of the Student Non-Violent Coordinating Committee (SNCC).
Step-by-step explanation:
The protest tactic initiated by Black students in Greensboro, North Carolina was the sit-in. On February 1, 1960, four students from the North Carolina Agricultural & Technical College conducted a peaceful protest at the segregated Woolworth's lunch counter. Labeled as the Greensboro Sit-Ins, these actions were a strategic form of protest that quickly gained traction, spreading to over one hundred cities and ultimately leading to the formation of the Student Non-Violent Coordinating Committee (SNCC).
The sit-ins were a direct challenge to the policies of racial segregation prevalent in the southern United States at that time. Through their refusal to leave the lunch counter until they were either arrested or served, the Greensboro Four, as they came to be known, set in motion a student phase of the African American civil rights movement. Their action was met with increased support as the days passed, and despite facing hostility, these protests were successful, pushing for desegregation at Woolworth's and other establishments.