Question

Which of these lines from “The Raven” by Edgar Allan Poe helps to create the dark and gloomy tone of the poem?

Answer 1

The lines from "The Raven” by Edgar Allan Poe which help to create the dark and gloomy tone of the poem are your second option:

 
Once upon a midnight dreary, while I pondered weak and weary,
Over many a quaint and curious volume of forgotten lore—

It is midnight, so it is dark. Dreary means gloomy, so this should be the correct answer.

Answer 2

Once upon a midnight dreary, while I pondered weak and weary,
Over many a quaint and curious volume of forgotten lore