According to the passage, lean production techniques work best ____.

For nearly a decade now, the manufacturing of
automobiles has been undergoing radical changes.
The principle cause is the introduction of new
production and management techniques, originally
engineered by Toyota and subsequently applied by
other Japanese car manufacturers. This is called
“lean” production. It implies no less a revolution in the
process of car manufacturing than the mass
production Henry Ford introduced at the beginning of
the century. In fact, lean production combines the
advantages of craft and mass production. A vital
feature of this production technique is that it achieves
its highest efficiency, quality and flexibility when all
activities - form design to assembly - occur in the
same area.