An expository essay needs to avoid these pronouns:

The correct answer is: 1st and 2nd person pronouns

OPTION 3 is the correct answer. 1st and 2nd person pronouns are need to be avoided in an expository essays. Because, it should be objective and should not trigger the readers as well as writers. So, it should not use those pronouns instead, it can use other pronouns or can be written in general form.