Unreliable narrator refer to the narrator whose point of view has been seriously compromised
Usually, if in the beginning of the story the narrator admit that he's mentally ill or he's one of the character of the story could be used as a clue
hope this helps
B. Novels have simple straightforward themes (and few of them).
Give you their denotations.
It seems that you have missed the necessary options for us to answer this question, so I had to look for it. Anyway, based on the given lines above, the literary device that Sophocles uses in these lines to keep the audience interested is DRAMATIC IRONY. Hope this helps.