Answer:
b. he's amused.
Step-by-step explanation:
When the speaker initially hears the noise caused by the raven, he is a little nervous about it, as he does not know what is the source of the noise. However, when he find out that it was only the raven, he is amused. We learn that the presence of the raven even makes the speaker smile:
Then the ebony bird beguiling my sad fancy into smiling,
By the grave and stern decorum of the countenance it wore...