In the month of March, a department had $7800$ units in beginning Work in Process Inventory that were $70\%$ complete. During March, $30900$ units were transferred into production from another department. At the end of March there were $2400$ units in ending Work in Process Inventory that were $70\%$ complete. Direct materials are added at the beginning of the process while conversion costs are incurred uniformly throughout the process. The weighted$-$average method is used. How much are equivalent units of production for direct materials for March?

Select answer from the options below $-$ Incorrect!

$37980$ equivalent units of production

$29220$ equivalent units of production

$38700$ equivalent units of production

$41700$ equivalent units of production