The debits to Work in ProcessAssembly Department for April, together with data concerning production, are as follows: April 1, work in process: Materials cost, 3,000 units $ 8,504 Conversion costs, 3,000 units, 40% completed 5,821 Materials added during April, 10,000 units 25,416 Conversion costs during April 33,120 Goods finished during April, 12,000 units 0 April 30 work in process, 1,000 units, 40% completed 0 All direct materials are added at the beginning of the process, and the first-in, first-out method is used to cost inventories. The conversion cost per equivalent unit for April is a. $2.96 b. $2.88 c. $2.55 d. $3.31