plz help question C

Cullumber Corp, reported net incomes for the past three years as follows: During the 2023 year-end audit, the following items come to your attention: 1. Cullumber bought a truck on January 1,2020 for $103,900 cash, with an $7,900 estimated residual value and a six-year life. The company debited an expense account for the entire cost of the asset. Cullumber uses straight-line depreciation for all trucks. 2. During 2023, Cullumber changed from straight-line depreciation for its cement plant to double declining balance. The following calculations present depreciation on both bases: The net income for 2023 was calculated using the double declining balance method. 3. In reviewing its provision for uncollectible accounts during 2023, the corporation has determined that 18 is the appropriate amount of bad debt expense to be charged to operations. The company had used 1/2 of 1N as its rate in 2022 and 2021 when the expense had been $8,930 and $6,030, respectively. Cullumber recorded bad debt expense using the new rate for 2023 . If they had used the old rate, they would have recorded $2,900 less bad debt expense on December 31. 2023. Assume that the beginning retained earnings balance (unadjusted) for 2021 was $641,000. At what adjusted amount should the beginning retained earnings balance for 2021 be shown, assuming that comparative financial statements were prepared