In 2007, Peggy, a widow, places $3 million in trust, life estate to her children, remainder to

Question:

In 2007, Peggy, a widow, places $3 million in trust, life estate to her children, remainder to her grandchildren, but retains the right to revoke the trust. In 2011, when the trust is worth $3.1 million, Peggy rescinds her right to revoke the trust. Peggy dies in 2013 when the trust is worth $3.2 million. What are Peggy's transfer tax consequences in:
a. 2007?
b. 2011?
c. 2013?