Answer:
C. Seriously
Explanation:
If you replace "gravely" with each of the answers, seriously makes more sense :)
You could add an “in” and make it “inconvenient”. Or you could say “cumbersome”
They should appear in order as they are cited within the essay. If you have a citation in the first paragraph, a citation in the second, and a citation in the third, it should be in chronological order of your citations (not chronological as in year/date of publications)