A manufacturing plant uses 2 kanbans to deliver inputs from its suppliers to the assembly line.

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A manufacturing plant uses 2 kanbans to deliver inputs from its suppliers to the assembly line. When a kanban is empty, it is sent back to the supplier for replenishment. The operations manager increases the number of kanbans from 2 to 4 to meet a sudden rise in demand. Which of the following decisions should the manager make to ensure that the input inventory is not overstocked when the demand subsides?