The purpose of theme is to -- O clarify the topic of a literary work
O convey the author's attitude toward a subject
O reveal an insight about human life
O teach the reader a moral lesson

O Teach the reader a moral lesson.

Explanation:

Any form of literary work tends to have a theme that resonates with what the writer wants to relay as a message to the readers. This purpose of a "theme" is thus, to provide a moral lesson through the story.

A theme is a central topic around which the whole story revolves around. Writers employ themes to pass on a message in their stories, be it a moral lesson or any message that they want to help spread. Themes are a particular favorite of morality plays which mainly focus on the Christian belief of goodness and humility. William Shakespeare's play "Macbeth" can be taken as an example of a theme based on 'good vs. evil'.

the sentence that avoid faulty coordination is:

culture, which is well represented in philadelphia, plays a major role including theatre, music, and the visual arts.  

faulty coordination occurs when the writer gives equal importance two different ideas (clauses) which in fact are not equivalent. in order to correct a misplaced clause or idea, the writer can place less important or emphatic ideas in a relative clause as in the previous sentence.