The Assembly Department had 4,900 units of beginning inventory in September​, and 5,700 units were transferred to it from the Cutting Department. The Assembly Department completed 3,100 units during the month and transferred them to the Packaging Department. Determine the total number of units to account for by the Assembly Department.
A. 8,000 units
B. 3,100 units
C. 10,600 units
D. 4,900 units