In Which of the Following Independent Situations Has Trent Made

In which of the following independent situations has Trent made a gift?

A) Trent established an irrevocable trust, income payable to himself for life and, upon his death, remainder to his children.
B) Trent dies owning a U.S. savings bond with ownership listed as: "Trent, payable to Sue on Trent's death." Sue redeems the bond.
C) Trent sends $25,000 to Alice's oral surgeon in payment of her dental implants. Alice is Trent's sister and does not qualify as his dependent.
D) Trent pays Eva $800,000 in a property settlement of her marital rights. One month later, Trent and Eva are divorced.