Through repetition, O'Brien wants to emphasize the automaticity and repetitive training that soldiers resort to in times of stress, as shown in option D.
We can arrive at this answer because:
O'Brien wants to give a realistic account of how soldiers live in the face of war.
In addition to the dangers and fears they faced, soldiers live in a constant monotony.
This monotony and the harsh environment develop a great sense of stress in everyone.
This allows them to deal with stress through repetitive thoughts and automatic actions that are highlighted through the use of repetitions.
"Where Have you Gone, Charming Billy?" is a story that will show the feelings of fear, loneliness, and hopelessness of soldiers in the Vietnam war.
Answer: C. The design of the Boeing 787 Dreamliner has also taken noise pollution into account, and boasts noise-reducing chevrons on its engine housings.
