Presuming the Year 2009 Is Involved,which,if Any,of the Following Disclaimers

Presuming the year 2009 is involved,which,if any,of the following disclaimers was wise from a tax standpoint?

A) Sid,the only son,disclaims $500,000 of his $3,500,000 inheritance in favor of his mother,who receives $2,000,000.
B) Faith,the surviving spouse,disclaims $500,000 of her $2,000,000 in favor of the children,who receive only $3,000,000.
C) Aubrey,the surviving spouse,disclaims $500,000 of her $1,000,000 to the children,who receive $3,500,000.
D) Leona,the surviving spouse,disclaims all of her $2,000,000 in favor of the Salvation Army (a qualified charity) .
E) None of the above.