Watkins Company had the following production for the month of June:

Units

Work$-$in$-$process, June $16,000$

Started during June $24,000$

Completed and transferred to finished goods $18,000$

Abnormal spoilage incurred $3,000$

Work$-$in$-$process, June $309,000$

Materials are added at the beginning of the process. As to conversion cost, work$-$in$-$process was $20\%$ complete at the beginning and $70\%$ complete at the end of the month. Spoilage is detected at the end of the process.

$19-4.$ Using the first$-$in$,$ first$-$out $($FIFO$)$ method, the equivalent units for June, with respect to conversion cost, were

a$.26,100.$

b$.23,100.$

c$.22,500.$

d$.19,500.$