Alphonse Bona carries on a business as a sole proprietor in which a single product is sold to retail customers. During his first year of business, purchases of inventory are as follows: On December 31, the fiscal period of the business, there are 19,400 inventory units on hand. It is estimated that these units have a replacement cost of $2.90 per unit and a net realizable value of $3.18 per unit. Required: Calculate the various closing inventory values that could be used to determine business income. Your answer should indicate the valuation method being used that you recommend to minimize taxes