Concept:Reducing-balance depreciation is charged on the net book value at the start of each year, not on the original cost.Explanation:Cost of assets as at 01/01/2018 is ₦600,000.Depreciation for 2018: 600,000×15%=N90,000.Net book value on 31/12/2018: 600,000−90,000=N510,000.Depreciation for 2019: 510,000×15%=N76,500.Net book value on 31/12/2019: 510,000−76,500=₦433,500.Answer:₦433,500 (Option C).