Julie, being self-employed, is required to make estimated payments of her tax liability for the year. her tax liability for 2018 was $25,000, and her agi was less than $150,000. for 2019, julie ultimately determines that her income tax liability is $18,000. during the year, however, she made the following payments, totaling $13,000. calculating total payments. the entry is on the left, and the amounts are listed in one column on the right. line 1. april 15, 2019. $4,500. line 2. june 17, 2019. 2,800. line 3. september 16, 2019. 4,100. line 4. january 2020. 1,600, underlined. line 5. total paid. $13,000, double underlined. because julie prepaid so little of her ultimate income tax liability, she now realizes that she may be subject to the penalty for underpayment of estimated tax. determine julie’s exposure to the penalty for underpayment of estimated tax. the same as part (a), except that julie’s tax liability for 2018 was $15,960.