5. BT&T Corporation manufactures telephones. Recently, the company produced a batch of 600 defective telephones at a cost of $9,000. BT&T can sell these telephones as scrap for $9 each. It can also rework the entire batch at a cost of $6,500, 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 $6,600.

Decrease by $3,500.

Increase by $5,500.

Decrease by $5,500.