The answer is Dante Alighieri, and it was written in 1320, and consists of three parts: Hell, Purgatory, and Heaven.
Their age is the difference
The correct answer is Sentence 9.
The sentence should be written: Sadly, even after that water is found, only some of it's clean and safe enough to drink.
We know an apostrophe should be placed here because we could also say: Sadly, even after that water is found, only some of it is clean and safe enough to drink.