A company is using a Kanban system with 3 containers, each holding 30 parts, between a downstream (using) and an upstream (producing) work center. The using work center can handle 300 jobs per day. The average elapsed time for the entire cycle is currently 0.25 days. The company is concerned about the safety factor for the operation. Which of the following is the safety factor () of the current operation? a. 90 percent b. 20 percent c. 17 percent d. 6 percent