How Did Slavery Differ in the Northern British Colonies Compared

How did slavery differ in the northern British colonies compared to the southern colonies before 1750?

A) Slavery never existed in the North.
B) Slavery was less extensive in the North because more white labor was available.
C) Almost no slaves performed agricultural labor because the North was mostly industrial.
D) Slaves had extensive legal rights in the North that were non-existent in the South.