Question

Which would best establish the mood of a story?

Answer 1

First is A) Imagery sets moods for stories

Second I assume is D) Fast and slow because it's an "exciting" text, but the dashes cause for a pause, almost like a comma or if to say "take a breath".

Answer 2

Actually, the first answer to your first question would be B) it determines the narrator's mood towards the subject or character. 

The second answer to the second question would be B) if you read the paragraph carefully the pace of the text seems to be fast.