Answer C: fear.
The passage gives the idea that John feels fear in anticipation to a bad approach with Carolyn based on his previous experience with her.
The word harbingers as it is used in this excerpt is a person or thing that announces or signals the approach of another.
B. Belle becomes less excited as the story goes on, until her excitement for bike riding disappears.
In grammar, an interjection is a word used to display emotions, such as surprise, glee, anger, etc. In this case the word "Yummy" is being used to display eagerness to enjoy the dinner that smells so unbelievably good.
Option A, "Yummy", is your correct answer choice.
Hope that helped! =)