Which of the following is NOT one of the principles for standard work practice at$$ Toyota?

Part $2$

A$.$

Improvements in the system must be made in accordance with the$$ "scientific method," at the highest possible level in the organization.

B$.$

Work is completely specified as to$$ content, sequence,$$ timing, and outcome.

C$.$

Internal and external$$ customer$-$supplier connections are$$ direct, specifying$$ personnel, methods,$$ timing, and quantity.

D$.$

Material and service flows are simple and directed to a specific person or machine.