Inacio Corporation uses the weighted$-$average method in its process costing system. Data concerning the first processing department for the most recent month are listed below:

Beginning work in process inventory:

Units in beginning work in process inventory $2,400$

Materials costs $ $14,500$

Conversion costs $ $6,600$

Percent complete with respect to materials $75\%$

Percent complete with respect to conversion $20\%$

Units started into production during the month $11,100$

Units transferred to the next department during the month $10,000$

Materials costs added during the month $ $173,600$

Conversion costs added during the month $ $243,600$

Ending work in process inventory:

Units in ending work in process inventory $3,500$

Percent complete with respect to materials $90\%$

Percent complete with respect to conversion $30\%$

The cost per equivalent unit for materials for the month in the first processing department is closest to:

$$12\mathrm{.}83$

$$14\mathrm{.}30$

$$11\mathrm{.}58$

$$11\mathrm{.}89$