Which word signals a cause?
O so
O then
O since
O therefore

we need more information in order to answer.

first of all, dante wanted to write an account of the search for spiritual atonement and salvation, and this desire drew heavily from dante's own experiences. dante was living in exile while writing inferno and so, much like his poetic counterpart, he felt like he had lost his way and needed direction.

explanation:

the positive connotations of the words "pretty," "quiet," and "silence" give the excerpt a tone of nervousness. i think its this