I believe the correct answer is: E. Those two old brothers had been having a pretty hot argument a couple of days before, and had ended by agreeing to decide it by a bet, which is the English way of settling everything.
As the figure of speech, satire is the term used to describe “the use of humor, irony, exaggeration, or ridicule to expose and criticize people's stupidity or vices, particularly in the context of contemporary politics and other topical issues.”
In this excerpt from Mark Twain’s “The £1,000,000 Bank-Note", the example of satire is the sentence:
“Those two old brothers had been having a pretty hot argument a couple of days before, and had ended by agreeing to decide it by a bet, which is the English way of settling everything.”
as it ridicules English way of settling everything with a bet.