Answer:
D) $0
Step-by-step explanation:
The depreciation method changed, but the previous depreciation expense has already been recorded and subject to taxes. Therefore the new straight line depreciation should start with the remaining asset value and calculate the depreciation expense for the remaining 6 years:
For example, if the purchase value was $1,200,000 (= $300,000 x 4), the remaining value would be $675,000 then the depreciation expense will be $112,500 per year during the next 6 years starting on year 9.