Answer:
The goal of the porter is to serve as an alert to the reader that something terrible is going to happen in the castle.
Explanation:
When the porter refers to hell, he warns the reader that something big and so terrible is going to happen that can be compared to hell and all the wickedness and agony that this place symbolizes. This situation is the murder of the king in cold blood and the ususpation and persecution that the murderer will provoke, as well as all the mental lack of control and emotional exhaustion that will be presented during the narrative.
Questions like this are difficult to answer without more context, although there are some clues about the symbolism in this brief excerpt. You can read the whole short story here: http://images.pcmac.org/SiSFiles/Schools/AL/MobileCounty/TheodoreHigh/Uploads/Forms/Reading_Packet_with_Text_-_The_Rockpile_by_James_Baldwin_-_20150323.pdf
In the story, boys are always getting hurt. Some boys are afraid to play there because it is dangerous. The provided passage also talks about fighting and danger. If this were my assignment, I would choose C) It shows its dangers.
There was a boy name Alan, he wanted to stay home and things started getting weird... he saw things flying off the walls and he died that night. Not before leaving his everlasting print on his parents house