It is an exclamatory sentence it should end in (!)
If the story would have been from Laurie's perspective, A. The audience would have been afraid of Laurie's mother because Laurie is so afraid of her, and C. The audience might have known that Laurie was misbehaving at school and making up the "Charles" character to mislead his mother.
It is clear that Laurie is afraid of his mother, he wouldn't have invented Charles to cover up for his misbehaving otherwise. This fear would have appear in the story, as well as the truth of his behaviour.
