Bob died leaving a will that passes all his assets to his wife outright, but with a provision that if she chooses to exercise a qualified disclaimer over any of his assets, all properly disclaimed assets will pass to a trust that holds the assets during his wife's life, providing her with income for life and a power to invade the principal as she needs for her health, support, and maintenance. At the time of Bob's death, the unified credit applicable exclusion amount equals $1 million since he died in 2013. Bob's estate is worth $750,000 million. The wife has an estate of approximately $500,000 she inherited from her parents.. The wife wants to control as much as possible of both of their assets. Yet, she also wants to disclaim enough assets to avoid a"stacking" of assets in her estate which could produce a higher estate tax at her death. Her planners advise her that her projected income stream from the combined assets will be sufficient to support her lifestyle however there will not be much growth in the combined estates remaining value. What is the minimum amount of Bob's estate that his Wife should disclaim to avoid a potential stacking of assets in her estate?

a. $500,000

b. $250,000

c. $750,000

d. $1.25 million