Answer:
D). Mystery.
Step-by-step explanation:
The mood is exemplified as the ambiance or atmosphere created by the author to offer an emotional environment that surrounds the audience/readers and help evoke the desired emotional response from them.
In the given excerpt from Edgar Allan Poe's "The Raven", the rhyme of the words 'rapping' and 'tapping' create a mood of 'mystery' and 'terror'. The speaker discusses that someone came there 'tapping suddenly' that offers a 'mystery' and the arrival of an unknown visitor who is knocking at his 'chamber door' constantly troubles him. Thus, these words supplement to create a 'mystery' and hence, option D is the correct answer.