Which One of the Following Best Illustrates Cognitive Dissonance

Which one of the following best illustrates cognitive dissonance?

A) Frannie is shocked to hear that her best friend Meghan, seemingly a very honest person, cheated on a math quiz.
B) Leo has a crush on his art teacher, even though she's more than ten years older than he is.
C) Jasmine loves science this year because her teacher uses many hands-on activities to make abstract concepts concrete and understandable.
D) Howie can't decide whether he wants to be a firefighter or a veterinarian when he grows up.