Able Towing Company purchased a tow truck for

$60,000 on January 1, 2017. It was originally depreciated

on a straight-line basis over 10 years with an

assumed salvage value of $12,000. On December 31,

2019, before adjusting entries had been made, the

company decided to change the remaining estimated life to 4 years (including 2019) and the salvage value to

$2,000. What was the depreciation expense for 2019?

(a) $6,000.

(b) $4,800.

(c) $15,000.

(d) $12,100.