In Act 4 of "Macbeth," identify a specific example of personification and explain its purpose or effect.
a) The purpose is to humanize the setting, emphasizing its significance to the characters.
b) The purpose is to elevate the mood of the scene, creating a sense of harmony.
c) The purpose is to intensify the atmosphere, heightening the tension and suspense.
d) The purpose is to highlight Macbeth's internal conflict, revealing his inner turmoil.