The Great Migration on the US home front during World War I involved

African Americans moving south from the North to work in factories.

African Americans moving north from the South to work in factories.

women joining the military in massive numbers to fight overseas.

women taking high-level government jobs left by men who were drafted.

African Americans moving north from the South to work in factories.

Explanation:

The Great Migration started in 1916, two years after World War I started, and lasted until 1970.

It consisted on the migration of hundreds of thousands of African Americans from the South to the industrial cities in the North. The motivation was economic: most African Americans lived in poverty in the South and the industrial jobs in the North paid better wages.