uinn paid $9000 of state and local taxes (SALT) in 2020. He used standard deduction in his 2020 federal income tax return. In 2021, he received a $1,500 state income tax refund due to his overpayment of state income tax in 2020. How much of the state refund has to be included in his 2021 taxable income (2020 standard deduction is $12400)? A. $1,600 B. $1,500 C. $500 D. $0