The correct answer is the following.
Before assembly lines: cars took longer to build.
Both: cars were made in factories, cars were made by people.
After assembly lines: cars were less expensive.
The introduction of the assembly line by Henry Ford on December 1, 1913, changed the way cars were produced in America. Ford had hired the services of the great scholar Frederick Taylor to devise a better way to improve the time and quality of the car's production process and that is how Ford came up with the moving assembly line that mass-produced cars and improved the productivity of the factory.