Able Towing Company purchased a tow truck for $60,000 on January 1, 2012. It was originally depreciated on a straight-line basis over 10 years with an assumed salvage value of $12,000. On December 31, 2014, before adjusting entries had been made, the company decided to change the remaining estimated life to 4 years (including 2014) and the salvage value to $2,000. What was the depreciation expense for 2014?

(a) $6,000.

(c) $15,000.

(b) $4,800.

(d) $12,100.