Need computation

In a process with 900 units of beginning Work in Process, the company completed and transferred out 10500 units during a period. There were 4800 units in the ending work in Process that were 45% complete as to conversion costs. Materials are added 70% at the beginning of the process and 15% when the units are 80% complete. How much is equivalent units of production for the period for material costs if the weighted average method is used? 13650 equivalent units O 15300 equivalent units O 12600 equivalent units 13860 equivalent units