Final answer:
Derek does not need to include any portion of the $1,806 state tax refund in his 2021 gross income because he took the standard deduction and did not itemize in 2020.
Step-by-step explanation:
As a cash basis taxpayer, Derek must include in his gross income for 2021 all refunds of state income tax that he deducted in a prior year to the extent that the deduction reduced his taxable income. Since Derek elected to take the standard deduction in 2020, he did not itemize deductions and therefore did not receive a tax benefit from the state tax payments. Consequently, none of the $1,806 state tax refund Derek received in 2021 is taxable, and he should include $0 of the refund in his 2021 gross income.