[2] A small concrete mixer has been bought for 20.000 TL . It has a salvage value of 2.000 TL at the end of a useful life of 4 years. Calculate yearly depreciation and book value by using: a) The straight-line method of depreciation b) The double-declining-balance method of depreciation c) The declining-balance method of depreciation d) The sum-of-the-years-digit method of depreciation