Department S had no work in process at the beginning of the period. It added $10,200$ units of direct materials during the period at a cost of $$71,400$; $7,650$ units were completed during the period; and $2,550$ units were $34\%$ completed as to labor and overhead at the end of the period. All materials are added at the beginning of the process. Direct labor was $$51,100$ and factory overhead was $$9,200.$

The total cost of units completed during the period was

a$.$ $$99,448$

b$.$ $$53,550$

c$.$ $$107,711$

d$.$ $$129,253$