Egolf Corporation failed to include $300,000 of taxable interest income on its 2016 calendar year Form 1120. The gross income reported on the return was $4.7 million, and the return was filed on February 20, 2017. b. How would your answer change if Egolf's gross income reported on the 2016 return was only $1 million? a. What is the last day on which the IRS may assess additional tax for Egolf's 2016 taxable year?