A machine with a cost of $65,280 has an estimated residual value of $5,478 and an estimated life of 7 years or 19,311 hours. It is to be depreciated by the units-of- activity method. What is the amount of depreciation for the second full year, during which the machine was used 3,780 hours? Do not round your intermediate calculations. Oa. $17,056.29 Ob. $11,705.84 Oc. $8,543.14 Od. $12,778.13