Ommar Company has assembly department and testing department. the following is a summary of October 2020 Assembly department operations. Direct materials are added at the start of the process. Conversion costs are added evenly during the process. Ommar Company uses the FIFO method of process costing. Direct materials cost $ Conversion costs$ Work-in-process, beg.In Oct1 $18,000 11,000 Total costs added during October $70,000 63,000 Work-in-process, beginning inventory(October1) 1,000 units 40% degree of completion, ending work-in-process (October31) 1,500 units 60% degree of completion, 7,000 units started during October and 6,500 completed. The cost per equivalent unit of direct materials and conversion cost are:

a. $15 of direct materials and $6 of conversion

b. $12 of direct materials and $15 of conversion

c. $8 of direct materials and $4 of conversion

d. $10 of direct materials and $9 of conversion

e. $7 of direct materials and $12 of conversion