please need help on this. I will really appreciate it

Harold and Maude were married and lived in a common-law state. Maude died in 2018 with a taxable estate of $25.40 million and left it all to Harold. Maude's executor filed a timely estate tax return claiming the marital deduction for the property left to Harold including a valid portability election. Harold died this year, leaving the entire $25.40 milion to their three children.(Refer to Exhibit 25.1 and Exhibit25.2) Calculate how much estate tax is due from Harold's estate under the following two alternatives. a. Assume that neither Harold nor Maude had made any taxable gifts prior to this year. b. Assume that Harold and Maude each made a $1 million taxable gift in 2011 and offset the gift tax at that time with the applicable credit