Which of the Following Statements Is False in Relation to the Equitable

Which of the following statements is false in relation to the equitable doctrine of 'mutual wills'?

A) Mutual wills are the only binding method by which a testator can ensure that both the survivor and anyone else is provided for by will.
B) Equity does not prevent the survivor of a mutual will from altering his will.
C) Mutual wills arise to stop the survivor acting fraudulently by going back on the agreement he or she made with another.
D) Mutual wills prevent the survivor revoking his will and substituting another in its place.