Department A had no work in process at the beginning of the period, $19,000$ units were started during the period, $4,000$ units were $40\%$ completed at the end of the period, and the following manufacturing costs were debited to the departmental work in process account during the period $($assuming the company uses FIFO$)$:

Direct materials$$140,000$Direct labor$126,300$Factory overhead$46,200$

Assuming that all direct materials are placed in process at the beginning of production, what are the total equivalent units for conversion costs?

a$.23,000$ units

b$.19,000$ units

c$.16,600$ units

d$.17,400$ units