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 1,100 Materials costs $ 13,200 Conversion costs $ 5,300 Percent complete with respect to materials 75 % Percent complete with respect to conversion 20 % Units started into production during the month 9,800 Units transferred to the next department during the month 8,700 Materials costs added during the month $ 172,300 Conversion costs added during the month $ 242,300 Ending work in process inventory: Units in ending work in process inventory 2,200 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:

a. $15.74
b. $17.37
c. $16.99
d. $16.05