Answer: A) The personification of panting air contributes to a tone of hopelessness.
Explanation: The tone of a text or sentence is the author's or speaker's attitude towards the audience, the subject or even the characters of the text. In the given sentences from Little Dorrit by Charles Dickens, we can see an example of personification (giving human characteristics to non human objects or animals), in the phrase "as if the air itself were panting," this personification contributes to a tone of hopelessness.