African enslaved persons outnumbered free people 10 to 1 in Saint-Domingue, which led to

a massive and successful uprising.

a good education for Toussaint L'Ouverture.

the release of General Toussaint L'Ouverture by the French.

strong and relentless control by plantation owners

I believe the answer is: a massive and successful uprising

At that time, Saint Dominique (a territory controlled by the French Government) had the largest slave population in the Carribean territory, which enable them to produce a third of world's sugar production and half of coffee production. Realizing that they have the power in numbers, the slaves decided to banded up together and overthrew French's ruling

African enslaved persons outnumbered free people 10 to 1 in Saint-Domingue, which led to " strong and relentless control by plantation owners", since they were afraid that such a ratio would lead to a revolt.