Unit costs of the weighted-average and FIFO methods will differ significantly when A. physical inventory levels of work-in-process are small in relation to the number of units transferred out B. conversion costs per unit vary greatly and physical inventory levels of work-in-process ar small relative to the number of units transferred out C. direct materials or conversion costs per unit are similar and physical inventory of work-in-process are small relative to the number of units transferred in D. direct materials or conversion cost per unit vary greatly and physical inventory levels of work-in-process are large relative to the number of units transferred out E. direct materials or conversion costs per unit vary little from period to period