Why would a speaker use rhetoric?

to tell a story
to show similarities
to effectively persuade
to show differences

A speaker would use rhetoric to effectively persuade. This is because when a rhetorical question is asked, the reader keeps on thinking about the answer to a question until they find it in what they are reading and have an "aha" moment.

  i think you forgot to put the options but if your reffering to this question then your answer will be "b"  a. add "to" to the base form to create an adjective.b. when the subject of a sentence is singular, add "–s" to the base form.c. add "–ed" to irregular base forms to form the past participle.d. do not use a base form with plural subjects