The correct answer is A) the speech and actions of the characters.
The technique that Saki utilize most in the segment of "The Interlopers" to develop the theme of the story is the speech and actions of the characters.
"The Interlopers" is a story written by Saki. Is the story of two mortal enemies Ulrich von Gradwitz and George Znaeym. They are enemies because of the conflicts from the past between their respective families. They confronted themselves, try to get reconciliation and they finally understand that there circumstances beyond what they actually can control.