Final answer:
The subject of this question is English and the grade level is high school. The dialogue excerpt provided is from a play or script, where a character expresses disbelief in another character's claims.
Step-by-step explanation:
The subject of this question is English as it involves a dialogue between characters in a play or story. The excerpt provided is from a conversation in a play or script, where Wadsworth is expressing his disbelief in Mr. Boddy's claims. The line is a part of the dialogue that adds dramatic tension and reveals the character's skepticism.