Carrie knows that she can always count on her friend Steve to do what he has agreed to do, no matter what comes up; her friend Walt, on the other hand, often forgets or changes his mind. Carrie's friends differ most strongly on which of these Big Five personality supertraits?

(A) Neuroticism
(B) Conscientiousness
(C) Agreebleness
(D) extroversion
(E) Openness to experiencess