Supplier A who supplies vegetables of broccoli, lettuce and green lettuce, is more appropriate to use inventory policy of speculation due to the characteristics of the relatively long lead-time and less reliable supply chain. For this supplier it is better to have inventory level that able to fulfill the demand level that fluctuate frequently. And for other variety of vegetables delivered by this supplier, it is already proper to use inventory policy of postponement in correspond to the lead-time that is relatively short with reliable supply chain in term of both the amount delivered and strong bargaining power owned.