In this task, you are given an impractical statement. You are also given three reasons (associated with "A", "B", "C") explaining why this statement doesn't make sense. You must choose the most corresponding reason explaining why this statement doesn't make sense.

mom feels happy that I forgot her birthday
(A) mom is happy that her birthday is drawing near
(B)it isn't a happy thing that one's birthday is forgotten
(C)I'm so sorry that I forget my mother's birthday
B