an abort remark
or a word used to express a particular emotion
The answer is B. "Frightened."
You can draw the conclusion that the author is trying to communicate a frightened tone by the diction of the stanza. The following line of the text states: "In the silence of the night, How we shiver with affright..." This is a very telling detail that supports the idea that the author's tone was meant to be frightening.
1.It's A because 'as' should have been used, meaning 'which'. 'I will refuse his demands which are outrageous '.
2.But' unless' has nothing to do with the context provided in C because 'until' should have fitted here.
The correct answer is B: HOWEVER.
From the passage given above, it can be seen that the similarities between coal and petroleum is the principal subject of the passage. The author gives several points that are jointly shared by both coal and petroleum. The author only gives one contrast between the two and in the process of making the contrast, he used the word 'HOWEVER'. The difference that the author gives about coal and petroleum is in their formation.