Bobbie Black died unexpectedly and had executed a will.She was divorced.She left $20,000 to her friend Bernice and $20,000 to her friend Anne Marie.The also left $20,000 to an animal shelter to provide care for her dog, Gracie, for her life.The remainder of her estate she left to her former husband Paul (lucky guy) because she died leaving an estate of $6,000,000.00.

In the "residuary clause" of her estate it states as follows:

I direct that my Executor pay out of my residuary estate, without apportionment, all estate, inheritance, succession and other taxes (together with any penalty thereon), assessed by reason of my death to the United States Government, my state government or my municipal government.

Which beneficiarywill bear the tax burden of Bobbie's estate?Why?