Which of the following lines from king's letter is meant to be interpreted literally?

the quicksand of racial injustice to the solid rock of human dignity.
in any nonviolent campaign there are four basic steps.
there comes a time when the cup of endurance runs over.
men are no longer willing to be plunged into an abyss of injustice.

marriage difficulties adversely affect parent-child communication

as for symbolic actions, the narrator's tearing down the wallpaper in an attempt to find the "woman" in the wallpaper represents her struggle to retain or regain her sanity.   the wallpaper has been part of her confinement and by her tearing it down, she is freeing herself from that confinement.