Final answer:
Option (1), Macbeth's reference to the candle in line 25 symbolizes the fleeting nature of life, aligning with the play's overarching themes of life's brevity and existential futility.
Step-by-step explanation:
In line 25 of Shakespeare's Macbeth, the reference to the candle symbolizes the fleeting nature of life. This is evident as later in Act V, Macbeth says, 'Out, out, brief candle!' which reflects his realization that life is transient and short-lived, much like a candle's flame that quickly extinguishes.
This notion fits within the broader themes of the play surrounding the brevity of human existence and the ultimate futility of one's actions, rather than representing darkness in Macbeth's heart, foreshadowing the upcoming murder, or highlighting supernatural elements directly.