A work centre uses an average of 50 parts per hour. A standard sized container holds 20 parts. On average it takes 30 minutes for a contained to complete the circuit from a kanban being received until the container is returned full. If the policy is to use a safety stock of 10% (\% of usage during the lead time), how many kanbans should be used? (rounding up to provide a relatively loose system). Multiple Choice 3 1 4 2