A pump of cost 4000 rupees is installed in a plot. The life of pump is 5 years. The salvage value of the pump is 0 after the end of 5 years. Estimate the pump value after depreciation by double declining balance method at the end of 4 years. a) 2624 rupees b) 2780 rupees c) 2916 rupees d) 2788 rupees