On 1 July 2011,Green Ltd Had Office Supplies Costing $20

On 1 July 2011,Green Ltd had office supplies costing $20 000.During the year ended 30 June 2012,the company purchased supplies costing $32 000.Of these,$4000 worth was returned to the supplier as unsatisfactory.At 30 June 2012,it was ascertained that $7000 worth of the supplies remained unused.What was the value of Green Ltd's office supplies expense for year ended 30 June 2012?

A) $7000
B) $41 000
C) $45 000
D) $25 000.