Why Do People Often Experience Post Decision Dissonance

Why do people often experience post decision dissonance?

A) Almost every alternative has both an upside and a downside, and this makes people feel uncomfortable.
B) People fear that indecision will be evaluated negatively by others.
C) People tend to find most decisions difficult.
D) People are motivated to believe in a just world.
E) It's easier to value an option we've chosen than to disparage an option we've rejected.