Chae Corporation uses the weighted-average method in its process costing system. This month, the beginning inventory in the first processing department consisted of 500 units. The costs and percentage completion of these units in beginning inventory were: Costs Percent Complete Marginal costs... 7,100 75% Conversion costs... 5,700 25% A total of 8,100 units were started and 7,500 units were transferred to the second processing department during the month. The following costs were incurred in the first processing department during the month: Marginal costs... 136,800 Conversion costs... 322,400 The ending inventory was 80% complete with respect to materials and 75% complete with respect to conversion costs. Note: Your answers may differ from those offered below due to rounding error. In all cases, select the answer that is the closest to the answer you computed. To reduce rounding error, carry out all computations to at least three decimal places. How many units are in ending work in process inventory in the first processing department at the end of the month? A) 1,100 B) 900 C) 600 D) 7,600