Units started into production were 28,000 and ending work in process units were 4,000. Given this, how much is the conversion cost per unit if ending work in process was 25% complete, and total materials costs and total conversion costs equaled $25,000 and $125,000, respectively? Select one: a. $6.00. b. $5.00. c. $5.17. d. $4.31. e. $4.46. f. This is not able to be determined from the provided information