Answer: I believe it would be letter (b)
Explanation: I had to answer this question yesterday and I am pretty sure this is the answer. Because it asks ¨the narrator gives an example of why oxygen is vital to climbers on Mt. Everest. How does the narrator develop this concept in the rest of the narrative?¨ so this is really the only plausible answer regarding the question.
The formal discussion is very correct and serious, rather than relaxed and friendly, and it is used especially in official situations.
Topics that are best suited for formal discussion are:
scientific discovery, literary analysis and medical diagnosis.
literally just took this hun !
Well a digression is a temporary departure from the main subject in speech or writing. So because the person writing the paragraph getting ill last year has nothing to do with this years cookie sale, I think you are correct, sentence 3 is an example of a digression. So D is the answer.
Whats the question? ill try to help