I need the entire sentence for context before I can answer the question. All of these options could be a subject, but you need to give context.
As there is no passage to compare to Poe´s story,here is a list of some characteristics of Gothic literature that may help you to compare both texts:
The main traits of Gothic literature are mystery and the presence of supernatural elements. Like in the "the Raven", Gothic style aims at creating a mood of fear, anxiety, terror and /or horror by playing with reality. The reader will soon be questioning what is written.This chaos of intrincate plots is narrated in an elaborate writing style.
Answer:
Area of pyramid = 14 square meter
Explanation:
Area of one right angled triangle 
(base) (height)
Put base 
m, height 
m
Area of one right angled triangle (2)(2.5) = 2.5 square meter
Area of 4 right angled triangles 
square meter
Area of square = side × side = 2 × 2 = 4 square meter
So,
Area of pyramid = 10 + 4 = 14 square meter
"Impact" is an effect.
So "impact" of the death means: the effect that death has on something.
For example, you could say:
The Impact of the death of the Emperor was the loss of respect for the country from the neighboring countries.
or you could say:
The impact of the death of her mother on her was devastating.
