Which of the Following Statements Is True in Relation to Establishing

Which of the following statements is true in relation to establishing that wills were intended to be mutual?

A) Evidence of an agreement between the parties is sufficient; a similar standard required for the imposition of a secret trust.
B) The testators need only establish a clear understanding that they not to revoke their wills after death.
C) The testators must have entered into a binding contract not to revoke their wills after death.
D) The testators need to enter into an agreement akin to a binding contract, but there is no requirement that they provide consideration to make it a valid contract between them.