Which of the following is a correct example of the plural possessive case a men's plans b. it's place c. stone's throw d. women's plans

Based on the answer choices given:

there are 2 (TWO) correct answers:

[A] men's plans ; AND:
[D] women's plans .

However, if you meant to write the answer choices as:

(a) men's plans; 
(b) it's place ;
(c) Stone's throw;
(d) woman's plans ;

than the answer would be: [A]: men's plans .

Note: "woman" is singular; so "woman's plans" would be "SINGULAR possessive";

whereas:  "women" is plural (more than one WOMAN)—the plural of "woman" is "women"; so "women's plans" would be "PLURAL possessive".

Likewise:

"man" is singular; so "man's plans" would be "SINGULAR possessive";

whereas:  "men" is plural (more than one MAN)—the plural of "man" is "men"; so "men's plans" would be "PLURAL possessive".

Hope this explanation helps!

Not sure if there was any sort of picture or something to go along with this but my guess is the book went into deep depth and was very informative.