After Giving the Matter a Great Deal of Thought, Iris

After giving the matter a great deal of thought, Iris declared chemistry rather than physics as her major. Having made this decision, she went out and had a good time with her classmates, who reminded her what a great friend she was. At that point, Iris was able to look at her choice and see both its pros and cons without glamorizing it. Her behavior can best be explained by the concept of

A) self-perception.
B) cognitive dissonance.
C) impression management.
D) self-affirmation.