Limbo is where unchristian and pagans go in the after life while the second circle(which i'm assuming you're talking about) is where sinners of Lust go.

D) It is ironic that Aunt Polly is so strict outwardly with Tom and so tender-
It is ironic that Aunt Polly is so strict outwardly with Tom and so tender-hearted toward him inwardly.
A dependent clause cannot stand alone : An independent clauses expresses a thought on its own