Which of the following is not true about lean systems?
a. The lean system is based on the philosophy of eliminating waste and utilizing the full capability of the worker
b. The objective of lean is to improve return on investment
c. Lean has its roots in repetitive manufacturing
d. In lean, the master schedule, or final assembly schedule, is kept flexible, rather than fixed, to allow work centers to meet work schedules
e. All of the above statements are true