During 2020, Mark's employer withheld $2,000 from his wages for state income tax. Marl claimed the $2,000 as an itemized deduction on his 2020 federal income tax return. His total itemized deductions for 2020 were $15,000 (the 2020 standard deduction was $12,400). Mark's taxable income for 2020 was a negative $25,000 due to substantial business losses, Mark received the $2,000 as a refund from the state during 2021. What amount must Mark include in income in 2021? SO $1,000 $2.000 $6,000