Both men's plans and women's plans are the correct examples of the plural possessive case, whereas <em>it's place </em>and <em>stone's throw </em>are not. The option <em>it's place </em>isn't even possessive, because <em>it's </em>stands for <em>it is, </em>and the word <em>its, </em>without the apostrophe would be possessive. The option <em>stone's throw </em>is not plural.
