The answer that best describes the tone in those lines is b, lonely.
I feel like it's implying that, Britannia is in a very very weary deep thought process.
I mean, droops can be referred to weary, and pensive means thought, or a deep thought.
However, weary could be tired. This is completely an assumption.
They give the piece a dreary, melancholy tone.
The imagery of these quotes are very dark and gloomy. They change the author's tone into a more dreary, melancholy tone.
