Use this information about Department $A$ to answer the question that follows, were $80\%$ completed as to labor and overhead at the end of the period. All materials are added at the beginning of the process, and the first$-$in$,$ first$-$out cost flow method is used.

The materials equivalent units of production for the period are

a$.29,000$

b$.39,000$

c$.32,000$

d$.29,800$