The correct answer to this problem would be the word theirs, the first one.
The usage of their/s is kind of a tricky one since it depends on what it usually is pertaining to in the previous lines. In this problem, it would refer to our presentation. If another word, let's say presentation, is added after the blank, then the answer would be their. In this case, there isn't anything after it so the answer would be theirs.
Those that have apostrophes on them aren't an option since it isn't applicable in this situation.
The author introduces very key details to the story to help introduce the ideas of September 11th
His breathing became heavy
Two main factors: The Norman invasion and political unification. The Norman invasion introduced a great many French loanwords, some 40% of English vocabulary by Chaucer's time.
Quotes, punctuation or descriptive words depending on the situation. (idk if this will help, need more context to fully understand the question)
