The correct response is:
Indentured servants agreed to work for no money in exchange for land and tools after a certain period of time, while slaves were forced to work indefinitely.
This accurately reflects the fundamental difference between indentured servitude and slavery. Indentured servants had contracts that allowed them to work for a specific period (usually several years) in exchange for certain benefits, while enslaved individuals were forced to work without any specified end to their servitude.