Amir’s projected tax liability for the current year is $23,000. Although Amir has substantial dividend and interest income, he does not pay any estimated taxes. Amir’s withholding for January through November of the current year is $1,300 per month. He wants to increase his withholding for December to avoid the penalty for underpaying estimated taxes. Amir’s previous year’s liability (excluding withholding) is $21,000. His previous year’s AGI did not exceed $150,000. What amount should Amir have withheld from his December paycheck? Explain.