Which rule should you follow to form possessive nouns?

Ato form the possessive of plural nouns that end in the letter s, add an apostrophe and s.

Bto form the possessive of most singular nouns, add just an apostrophe.

Cto form the possessive of plurals that do not end in s, add an apostrophe and s.

Ddo not use apostrophes to form the possessive of most nouns.