Please Answer this following problems and explain the work.

Use the following information for questions 4 to 8: - Cost: $10,000 - Salvage $1,000 - Useful life: 5 years - Units over life: 36,000 4. What is the fourth-year depreciation expense under the sum-of-years digits? A. $2,400 B. $1,000 C. $1,100 D. $1,200 5. Assume the asset produced 13,000 units. What is the depreciation expense under the units of production method? A. $1,300 B. $2,500 C. $3,250 D. $4,250 6. Assume the declining balance =200% method is used. What is the book value at the end of year 2 ? A. $6,000 B. $3,600 C. $2,160 D. $1,296