The correct answer is A.
The sentence should be written like this: <span>Sadly, even after that water is found, only some of it's clean and safe enough to drink.
Because the sentence is saying "only some of IT IS clean and safe enough to drink," an apostrophe should be used.
</span>
Hello!
By emphasizing the number of words in the poem and writing down the syllables by stressing certain words. <~ Hope this helps a little bit.. That's all I really know, haha!
Have A Wonderful Day! :)