Roland had a taxable estate of $5.5 million when he died this year. Calculate the amount of estate tax due (if any) under the following alternatives.

a. Roland's prior taxable gifts consist of a taxable gift of $1 million in 2005.

b. Roland's prior taxable gifts consist of a taxable gift of $1.5 million in 2005.

c. Explain how the tax calculation would change if Roland made a $1 million taxable gift in the year prior to his death.