Mayer Company has recently tried to improve its analysis for its manufacturing process. Units started into production equaled 18,000 and ending work in process equaled 1,200 units. Mayer had no beginning work in process inventory. Conversion costs are applied equally throughout production, and materials are applied at the beginning of the process. How much is the materials cost per unit if ending work in process was 25% complete and total materials costs equaled $72,000? $16.00. $4.21. $4.00. $3.75.