For each question, fill in the letter from the following list which best describes the presentation of the item on the financial st: of Helton Corporation for 2021. a. Change in estimate b. Prior period adjustment (not due to change in principle) c. Retrospective type accounting change with note disclosure d. None of these choices 1. In 2021, the company changed its method of recognizing income from the completed-contract method to the percentage-of-completion method. 2. At the end of 2021, an audit revealed that the corporation's allowance for doubtful accounts was too large and should be reduced to 2%. When the audit was made in 2020 , the allowance seemed appropriate. 3. Depreciation on a truck, acquired in 2018 , was understated because the service life had been overestimated. The understatement had been made in order to show higher net income in 2019 and 2020. 4. The company switched from a LIFO to a FIFO inventory valuation method during the current year. 5. In the current year, the company decides to change from expensing certain costs to capitalizing these costs, due to a change in the period benefited. 6. During 2021 , a long-term bond with a carrying value of $3,600,000 was retired at a cost of $4,100,000. 7. After negotiations with the IRS, income taxes for 2019 were established at $42,900. They were originally estimated to be $28,600. 8. In 2021, the company incurred interest expense of $29,000 on a 20-year bond issue. 9. In computing the depreciation in 2019 for equipment, an error was made which overstated income in that year $75,000. The error was discovered in 2021. 10. In 2021, the company changed its method of depreciating plant assets from the double-declining balance method to the straight-line method