The correct answer is B. To make it seem as if a character is telling the story
With the use of first person, a story seems like the character narrating it is explaining it themselves based off of their own experience. It also provides the perspective of that character, and can allow the reader to pick up on interprotations directly from the narrator’s experiences and views.
It is a bit confusing on why you said 40,0000 with four zeros But based my assumptions with calculations, here are my answers: 40,0000 with five zeros or 400,000÷60=6666.67 40,000 with four zeros=666.67