The Assembly Department of Interface, Inc., manufacturer of computers, had 4,500 units of beginning inventory in September, and 7,000 units were transferred to it from the Production Department. The Assembly Department completed 3,500 units during the month and transferred them to the Packaging Department. The weighted- average method is used. Calculate the total number of units to account for by the Assembly Department. O A. 7,000 units O B. 4,500 units O C. 11,500 units O D. 2,500 units