Following his death in 2014, Zane Wulster's gross taxable estate was valued at $6 comma 989 comma 000. He has made a total of $226 comma 326 of gifts that exceeded the annual gift tax exclusion. a. What is the amount of his gross gift-adjusted taxable estate? b.Are estate taxes payable? a. The amount of his gross gift-adjusted taxable estate is $ nothing. (Round to the nearest dollar.)