question for F3

What would be the effect on a company's profit of discovering inventory with cost of $1250 and a net realisable value of $1000,assuming that the same inventory had not been included in the original inventory count
A. an increase of $1250
B. an increase of $1000
C. a decrease of $250
D. no effect at all
小弟实在是看不懂这道题了，请各位前辈麻烦给解答一下

B.
Cost of sales= Purchases+opening inventory-closing inventory.
inventory should be recorded@ lower of cost ($1250) and NRV($1000). in this case should increase closing inventory by $1000.
Thus reduces cost of sales by $1000, increases profit by $1000.

非常谢谢了