Read these passages:

MACBETH. Stars, hide your fires
Let not light see my black and deep desires.

William Shakespeare, Macbeth, Act I, scene iv

LADY MACBETH. Come, thick night,
And pall thee in the dunnest smoke of hell,
That my keen knife see not the wound it makes.

William Shakespeare, Macbeth, Act I, scene v
These lines help to create a scary tone by:
A. expressing the idea that the characters know they are sinful and will probably be punished for their crimes.
B. creating a sense of evil and showing that both characters believe in supernatural elements.
C. showing that Macbeth and Lady Macbeth are in direct opposition and have a deep conflict.
D. using the image of darkness to imply that something bad will happen.