The main purpose of a thesis statement in a literary analysis essay is to introduce the topic of the literary analysis essay. Option 4 is correct.
The thesis statement of a literary analysis essay tells the reader what to expect: it constitute a restricted, precisely worded declarative sentence that states the purpose of your essay.
Literary analysis involves examining all the parts of a novel, play, short story, etc.
A verbal irony is an irony in which a person says or writes one thing and means another, or uses words to convey a meaning that is the opposite of the literal meaning.