ACME revised the expected service life on a truck, acquired in 2018, from 10 years to 6 years due to a change in usage. In calculating the depreciation in 2018 for buildings, an error was made which overstated income in that year by $ 75,000. The error was discovered in 2020. The company switched from average cost to FIFO inventory costing during the current year. 1. Change in Accounting Policy - Prospective Application 2. Change in Accounting Policy - Retrospective Application 3. Change in Accounting Estimate- Prospective Application 4. Change in Accounting Estimate - Retrospective Application