QUESTION 6 An unmarried taxpayer with AGI of $120,000 in 2021 has a tax liability of $21,000. The taxpayer's 2022 AGI and tax liability are $175,000 and $31,000, respectively. To avoid any penalty for underpayment of estimated tax in 2022, the minimum amount the taxpayer must prepay during 2022 is: $21,000. $23,100. $27,900. $31,000. $34,100. Paying 100% of the prior year's tax liability to avoid an underpayment penalty only works when a taxpayer's prior year's AGI does not exceed $