which best describes the irony in the ending of " Charles "?

a- the lighthearted tone of the story suddenly shifts as the narrator and readers are shocked by the truly terrible news given at the end of the story.
b- the humor disappears as the narrator and readers learn that the kindergarten teacher is the mother of Charles
c- the narrator and readers are surprised when they find out that Laurie is responsible for all the bad things he said Charles did
d- the narrator and readers are concerned when they learn that Charles hurts other children in the class