The options 'true' and 'false' don't change the language if the users or course language is changed.
I created a course/quiz with user language 'German' and english text. Afterwards I viewed the quiz in language settting English. The choice options 'Wahr' 'Falsch' didn't switch to English. I had to edit the question and to save it again. Then it was visible 'true/false'.
The screenshot shows the same question now when I look on the question with German language setting again.
I expected that this entry switches with the users/course language like all the other interface elements.