2.46 An assembly line conveyor system with a 5-year life is to be depreciated by the DDB method. The conveyor units had a first cost of $30,000 with a $9000 salvage value. The annual operating cost al- located to the conveyor is $7000 per year. The book value at the end of year 2 is closest to: a. $6,480 b. $10,800 $12,400 $18,000