When inventory costs are rising, a company may prefer to use the method in the perpetual system in order to pay the lowest amount of taxes.

LIFO (Last-in-last-out)

Explanation:

Last in last out is the method of inventory valuation where the unit that was added in inventory last would be sold first. In case, of rising prices, the unit added in inventory would cost more than the one added first. So, if LIFO is used in case of rising prices, cost of goods sold would be higher. If COGS is higher, income will fall, thereby reducing tax liability.

So, if the firm wants to pay lower taxes during price rise, it should opt for LIFO method to value inventory.