Which phrase can be used to describe author's purpose in an argument?

Appeal to the senses
Entertain the audience
Prove a position
Teach accepted facts

Prove a position

Explanation:

An author's purpose in an argument is to "prove a position." In order to do this, he tries to persuade the readers by providing evidence which supports his claim or position. It makes his stance clear by providing statements that will support his point-of-view. This is often used in "controversial issues."

So, this explains the answer.  

the characters in string all have major secrets that they strive to avoid revealing throughout the play.

well basically since ima beginner people will answer any subject "right away"and if you get more points you could ask more questions or if you answer someone's question you get points