Hello!
The statement that would best reflect what Garvey promoted would be the third option:
"African-Americans can best achieve equality by establishing their own nation"
Because Garvey advocated for the rights of people considered "black" and promoted the idea of creating a nation of their own in Africa, in this way the inequality that existed and was tolerated in the United States due to racial discrimination, could be faced, he believed that it was necessary for "black" people to create their own nation because they did not see it possible that they could be integrated into a society that marginalized them. That is why he founded the UNIA (Universal Association for the Improvement of the Black Man)
I hope this helps.
Greetings.