Bildy Corporation uses a process costing system. During January, 10,800 units were started, and 11,750 units were completed. On January 31, the inventory consisted of 550 units that were 60% completed. A reconciliation would determine the number of physical units in the beginning inventory on January 1. How many were there?
a) 400
b) 880
c) 1,500
d) 220