Cexecutive checks on legislative d judicial check on the executive

Option D.

Explanation:

Slave ships, is the right answer.

The term fugitive slaves are used to refer to those slaves who made successful attempts to run away from slavery. The appearance of slaves fleeing away and endeavoring to get freedom is as old as the system of slavery. Such slaves were slaves who run away and left their master. These slaves traveled without permission, they usually tried to reach those territories where slavery was banned. Accordingly, they used to walk, used railroads and wagons to run away.