A department adds all raw materials to a process at the beginning of the process and incurs conversion costs uniformly throughout the process. For the month of January, there were 20,000 units in the beginning work in process inventory; 80,000 units were started into production in January; and there were 30,000 units that were 30% complete in the ending work in process inventory at the end of January. What were the equivalent units of production for conversion costs for the month of January?

A. 79,000 units

B. 91,000 units

C. 89,000 units

D. 70,000 units

E. 100,000 units