Which One of the Following Situations Illustrates Extinction of a Classically

Which one of the following situations illustrates extinction of a classically conditioned response?

A) Alfonso thinks school is a waste of time because he doesn't learn anything he can use in his own life.
B) Brian experiences more and more anxiety about mathematics as his math problems become increasingly challenging.
C) Over time Carla becomes less nervous about tests because she finds that she can succeed at them.
D) Deirdre doesn't like keeping her desk clean because she has too much stuff to arrange it all neatly inside.