The narrator is invited to dinner as an anniversary of sorts that happened a long time ago, where he announced that he built a time machine. And then he arrives dirty and rugged beginning to tell the guests his story
I am sort of puzzled on this particular question; however, I think I solved it. Okay, so the text starts with explaining the benefits of coffee, then it proceeds to explain the negative affects of consuming coffee. Transition words like <em>on the other hand</em> are commonly used when contrasting ideas. Hence, I believe the correct answer is c. contrast.
Well the best way is to go to a dictionary but the best way without it at least for me is to look for context clues.
