EDH, Inc. purchased equipment at the beginning of 2017 for $180,000. EDH decided to depreciate the equipment over a 5-year period using the double-declining-balance method. EDH estimated the equipment's residual value at $30,000. Which of the following statements is correct concerning EDH's financial statements at December 31, 2017?

a the book value of the equipment of $108,000

b. the book value of the equipment is $72,000

c. the total accumalated depreciation is $90,000

d. depreciation expense for 2017 is $60,000