The Office Supplies Account Shows a Beginning Balance of $600

The Office Supplies account shows a beginning balance of $600 and an ending balance of $400. If office supplies expense for the year is $3,100, what amount of officesupplies was purchased during the year?

A) $3,500.
B) $3,300.
C) $2,700.
D) $2,900.
E) $3,700.