Department W had 2,400 units, one-third completed at the beginning of the period; 16,000 units were transferred to Department X from Department W during the period; and 1,800 units were one-half completed at the end of the period. Assume the completion ratios apply to direct materials and conversion costs. What is the total number of units to be assigned cost on the cost of production report for Department W?

a.12,000 units

b.18,500 units

c.17,800 units

d.13,600 units