Which describes a fall line?

Which describes a fall line?

The fall line represents the sharp drop from the plateaus in the Piedmont.

The fall line represents the area where the rivers run fast between the elevated Piedmont and the Coastal Plain.

The fall line represents the region where rivers in the Coastal Plain reach deep harbors of the coast.

The fall line represents the current coast of Georgia an the Atlantic Ocean.

The fall line represents the area where the rivers run fast between the elevated Piedmont and the Coastal Plain.