Callen Inc. has accumulated minimum tax credits of $1.33 million from tax years prior to 2018. The following are Callen's regular tax before credits for 2018 through 2021. 2019 2020 2021 2018 Regular tax before credits $115,000 $135,000 $105,000 $61,500 Complete the following table to calculate Callen's allowable minimum tax credit each year. (Negative amount should be indicated by a minus sign.) 2018 2019 2020 2021 Nonrefundable portion of minimum tax credit Refundable portion of minimum tax credit Total minimum tax credit used Callen Inc. has accumulated minimum tax credits of $1.33 million from tax years prior to 2018. The following are Callen's regular tax before credits for 2018 through 2021. 2019 2020 2021 2018 Regular tax before credits $115,000 $135,000 $105,000 $61,500 Complete the following table to calculate Callen's allowable minimum tax credit each year. (Negative amount should be indicated by a minus sign.) 2018 2019 2020 2021 Nonrefundable portion of minimum tax credit Refundable portion of minimum tax credit Total minimum tax credit used