The phrase "productive of astonishment and mirth" $($paragraph $4,$ last sentence$)$ is best described as

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AP English Language and Composition

Tes

DBW $1\mathrm{.}11-1\mathrm{.}15$

a deliberately puzzling paradox

a circumlocution for "appearing ridiculous"

an intentional shift in the level of diction

a sareastic interpretation of "embarrassing" $($paragraph $4,$ last sentence$)$

an authorial aside directed at the speaker's opponents