One tool of Lean that is a container, card, or visual limit that signals when work needs to be done or replenishment needs to be initiated is called a:

Kanban System

Explanation:

Kanban can be regarded as one of Lean tools which is been designed to carry out reduction of the idle time in a production process. The idea or concept behind this Kanban system, is to make delivery of needs of the process needs at exactly the it needs it. Kanban can be reffered to as visual cards. Kanban can as well be explained as scheduling system that is used for lean manufacturing as well as just-in-time manufacturing. Taiichi Ohno, who was an industrial engineer at Toyota carried out development of kanban so that there could be an improved manufacturing efficiency. Kanban is considered as one method used to achieve JIT.

It should be noted that Kanban System is One tool of Lean that is a container, card, or visual limit that signals when work needs to be done or replenishment needs to be initiated .

answer; geometric center line;