Read the quotation from "A Psalm of Life." Let the dead past bury its dead!

What is the effect of the repetition of the word “dead” in this line?
It serves as a reminder that the past is comprised of the actions of people now deceased.
It suggests that the reader should think of mortality when thinking of the past.
It reinforces the idea that one should live in the present, not in the past.
It creates a mood of foreboding, which affects the rest of the poem.