Though I see that many have asked the question of whether acronyms that ends with a "s" should be s' or s's, I have puzzled over whether nouns that ends in “s” should end in s's or s'.
Many sources online and in SAT books disagree with each other and I am confused because of all the disagreements.
If given the example:
Louis’s scarf
Louis’ scarf
One book stated that it was Louis's while another said that it should be Louis'.
I specifically looked for the answer what College Board's SAT would agree with and I would also like to know warrants to the answer as well.
