I think it's B. Teacher usually like longer short stories...
I don't think the answer is compressed, or narrow. I believe the answer is needlelike.
This is a theme. The difference between those two is that the plot is similar to the storyline, whereas themes are general thoughts being analyzed. In this case, this is a theme, whereas something more detailed with description of events would be a plot.
An onomatopoeia is a word that phonetically imitates, resembles or suggests the source of the sound that it describes. Onomatopoeia (as an uncountable noun) refers to the property of such words. Common occurrences of onomatopoeias include animal noises such as "oink", "miaow" (or "meow"), "roar" or "chirp". I don't know if you read comics but sometimes someone will hit something and it will say "BANG" it basically a sound.