BT&T Corporation manufactures telephones. Recently, the company produced a batch of 630 defective telephones at a cost of $9,300. BT&T can sell these telephones as scrap for $9 each. It can also rework the entire batch at a cost of $6,800, after which the telephones could be sold for $20 per unit. If BT&T reworks the defective telephones, by how much will its operating income change?

Increase by $6,930

. Decrease by $3,500.

Increase by $5,800.

Decrease by $5,800.