Hogan Company uses weighted average process costing system and started 30,000 units this month. Hogan had 12,000 units that were 20 percent complete as to conversion costs in beginning Work in Process Inventory and 3,000 units that were 40 percent complete as to conversion costs in ending Work in Process Inventory. What are equivalent units for conversion costs? a)37,800 b)40,200 c) 40,800 d)42,000