Sharp Offers an Example of Sally, a Widow in Her

Sharp offers an example of Sally, a widow in her mid-50s, whose son's heart had been transplanted into the body of Larry, a married man in his late 60s. Why, in Sharp's view, did the role of donor mother become so important for Sally and Larry, once they got to know each other?

A) It helped them deal with the "adulterous" overtones in their relationship.
B) It helped them deal with the "incestuous" overtones in their relationship.
C) Larry had never known his own mother.
D) Both a and b are true.