Because it leaves almost no trace and no symptoms yet can still kill you very quickly and effectively
The answer C correctly uses possessive form and is the right answer. It's not A because there is only one George so the apostrophe is in the wrong place. In B, there's not even an apostrophe and it's not clear as to whether there is only one cousin or two or more cousins. In answer D, here should not be an apostrophe for develops.
D How the character creates an effect
You don't know about me, without you have read a book by the name of The Adventures of Tom Sawyer, but that ain't no matter.
