Barbara, a Wealthy Widow, Promises the Pastor of Her Church

Barbara, a wealthy widow, promises the pastor of her church that she will donate $10,000 to the church to help pay off its mortgage if the stewardship committee can obtain enough pledges for the balance of the $30,000 mortgage.Other pledges are obtained to pay off the mortgage, but now Barbara has changed her mind and plans to take an around-the-world cruise instead.Barbara's promise to pay $10,000:

A) is enforceable because it is a new promise to perform a voidable obligation.
B) is a promise to give a gift and is therefore not enforceable.
C) is enforceable under the Restatement of Contracts.
D) was made to satisfy a preexisting moral obligation and is therefore enforceable.