Cinnamon Corp. started business in 2017 and uses the weighted average cost method. During 2017, it purchased 45,000 units of inventory at €10 each and sold 40,000 units for €20 each. In 2018, it purchased another 50,000 units at €11 each and sold 45,000 units for €22 each. Its 2018 cost of sales (€ thousands) was closest to:
A €490.
B €491.
C €495.
用WAC法计算存货成本，为什么不是（45000*10+50000*11）/95000=10.52来计算库存平均成本？
