In each of the following independent situations, what bypass (exclusion) amount is available to Ava's estate when she dies in 2017? Assume that any appropriate procedures are followed, and that elections are made to transfer to Ava any DSUE amount of Al, her deceased husband.
a. Al died in 2015 and did not use any of his bypass amount.
b. Continue with part (a). Ava remarried in 2016, and Andy, her second husband, had used $1 million of his bypass amount in making past taxable gifts. Andy predeceases Ava in June 2017.