Estate Finance Family Tax Planning Question

Grandfather dies in 2020 with $220,000 of GST exemption remaining and makes no affirmative allocation of GST exemption on his estate tax return. Grandfather made the following testamentary transfers at his death:

• $100,000 to Grandson

• $100,000 to trust that provides mandatory distributions of income to Grandson and upon Grandsons death is distributed to Grandsons issue.

• $100,000 to trust that provides mandatory distribution of income to Son for Sons life. Upon Sons death, the remainder of the trust is distributed to Grandson.

• $100,000 to trust that provides discretionary distributions of income and principal to Son and is distributed according to Sons general power of appointment at his death, or, in default of such power, to Grandson.

How much of each transfer receives grandfathers remaining GST exemption and why? What is the inclusion ratio of each of the three trusts?