Which Best Completes the Following Sentence? During the Production Era

Which best completes the following sentence? During the production era

A) the factory system brought together in one place all the materials and workers required to produce items in large quantities.
B) great emphasis was placed upon satisfying the customer.
C) the improved production output resulting from assembly lines was obtained by increasing worker freedom.
D) the presence of big firms aided individuals who wished to go into business for themselves.
E) Henry Ford introduced the first moving assembly line which brought automobile parts to the worker.