Bess, a widow, died in October 2017. Her gross estate, which totaled $7 million, included a $100,000 life insurance policy on her life that she gave away in 2015. The taxable gift that arose from giving away the policy was $15,000. In December 2014, Bess made a $740,000 taxable gift of stock whose value increased to $790,000 by the time Bess died. She owed debts of $80,000 at the time of her death.

a. What was her estate tax base?

b. What unified credit could her estate claim?