Wallace places emphasis on the word "adjust" because he is addressing our realities and way of thinking as "default." He expresses the importance of paying attention to your surroundings, and adjusting to other perspectives and ways of thinking. He compares our ignored experiences to the water fish swim in but were never taught to notice.
Your first option, "I have taken all the stress I can stand.", is a line of dialogue.
Dialogue is speaking/talking. The second and last options cannot be examples of dialogue because they are not being spoken (you can tell by the lack of quotation marks).The third option is also incorrect because it is what is written, as it says "the study reported" (the study does not speak). Therefore, the first option is correct.
B. A person must be acculturated.
