Good afternoon, Lacmobster!
The significance of the repetition of 'absurd' in The Importance of Being Earnest is that Jack most commonly use that word to describe the things that seems weird or crazy to him.
I hope this has satisfied your needs, and if you have anymore questions, feel free to ask. Have a good day!
The sentence that contains a misplaced modifier is C. My promises are as good as gold, which I never break.
The modifier "which I never break" modifies promises not gold.
The sentence should read like this, My promises, which I never break, are as good as gold.
C is an example of non-standard english