Kimbeth Manufacturing Makes Dust Density Sensors (DDS), a Safety Device

Kimbeth Manufacturing makes Dust Density Sensors (DDS) , a safety device for the mining industry. The company uses a process costing system and has only a single processing department. The following information pertains to operations for the month of May:
$\begin{array} { | l | r | } \hline & \text { Units } \\\hline \text { Beginning work in process inventory } & 16,000 \\\hline \text { Started into production during May } & 100,000 \\\hline \text { Completed during May } & 92,000 \\\hline \text { Ending work in process inventory } & 24,000 \\\hline\end{array}$
The beginning work-in-process inventory was 60% complete with respect to materials and 20% complete with respect to conversion costs. The ending work-in-process inventory was 90% complete with respect to materials and 40% complete with respect to conversion costs. The costs were as follows:
$\begin{array}{|l|r|r|}\hline & \text { Materials } & \text { Conversion } \\\hline \begin{array}{l}\text { Beginning work-in-process } \\\text { inventory }\end{array} & \$ 54,560 & \$ 35,560 \\\hline \text { Costs incurred during May } & \$ 468,000 & \$ 574,040 \\\hline\end{array}$


- Using the FIFO method,the cost per equivalent unit of materials for May is closest to which of the following?

A) $4.12.
B) $4.50.
C) $4.60.
D) $4.80.