Shakespeare's macbeth, act v scene 5

macbeth. she should have died hereafter;
there would have been a time for such a word.
tomorrow, and tomorrow, and tomorrow
creeps in this petty pace from day to day
to the last syllable of recorded time;
and all our yesterdays have lighted fools
the way to dusty death. out, out, brief candle!
life's but a walking shadow, a poor player
that struts and frets his hour upon the stage
and then is heard no more. it is a tale
told by an idiot, full of sound and fury,
signifying nothing.

which line refers to the meaninglessness of life?

a. "all our yesterdays have lighted fools/ the way to dusty death."
b. "to-morrow, and to-morrow, and to-morrow,/ creeps in this petty pace from day to day,"
c. "out, out, brief candle! "
d. "full of sound and fury,/ signifying nothing."