If you read each of these, or speak them, there is only one that suits the sentence correctly.
Go with the third one. Couldn't seems to fit pretty well there.
Answer:
5 stressed syllables each followed by an unstressed syllable.
Explanation:
I looked this up, not 100% tho
Answer:
Pensive
Explanation:
PENSIVE-
engaged in, involving, or reflecting deep or serious thought.
Hope this helps
Your purpose for writing the essay might be to persuade the reader to watch that particular TV show.
(As for the questions below, I think you have to answer those yourself based on the TV show you've chosen.)