This year, Santhosh, a single taxpayer, estimates that his tax llability will be $116,500. Last year, his total tax liability was $20,500. He estimates that his tax withholding from his employer will be $40,500. Required: a. Is Santhosh required to increase his withholding or make estimated tax payments this year to avoid the underpayment penalty? b. By how much, if any, must Santhosh increase his withholding and/or estimated tax payments for the year to avoid underpayment penalties? Complete this question by entering your answers in the tabs below. Is Santhosh required to increase his withholding or make estimated tax payments this year to avoid the underpayment penalty