Mary gave a $30,000 taxable gift (after the application of any relevant annual exclusion) to her son, George, in 2019. She reported the gift on a gift tax return, but paid no tax. In 2020, Mary died. How will Mary's 2019 gift affect her estate tax return?

The total amount that Mary's estate can pass on tax-free will be reduced by $30,000.

A tax on the $30,000 gift must be paid on the 2020 estate tax return.

Mary's estate will be subject to the generation-skipping transfer tax.

A $30,000 credit may be applied on the estate's Form 706.