Which excerpt from "the enigma machine" supports the idea that allied forces expected the germans to complicate their coding system?

Even though you didn't attach any options to choose the correct one I can give you one excerpt that will definitely help you to pick the right answer from your option list. Here you are : After 1938, when the Germans introduced additional rotors and plugs to increase the number of possible combinations, Polish and British cryptologists had already developed alternative methods of recovering the daily keys.