Sheffield Corp. which has a calendar year accounting period, purchased a new machine for $90000 on April 1, 2016. At that time Sheffield expected to use the machine for nine years and then sell it for $9000. The machine was sold for $49100 on Sept. 30, 2021. Assuming straight-line depreciation, no depreciation in the year of acquisition, and a full year of depreciation in the year of retirement, the gain to be recognized at the time of sale would be $0. $6100 O $4100 O $9000