Which line from "nothing gold can stay" contains an allusion?

nature's first green is gold,/ her hardest hue to hold.

her early leaf's a flower; / but only so an hour.

then leaf subsides to leaf./ so eden sank to grief,

so dawn goes down to day./ nothing gold can stay

Araby every morning i lay on the floor in the front parlour watching her door. the blind was pulled down to within an inch of the sash so that i could not be seen. when she came out on the doorstep my heart leaped. i ran to the hall, seized my books and followed her. i kept her brown figure always in my eye and, when we came near the point at which our ways diverged, i quickened my pace and passed her. this happened morning after morning. i had never spoken to her, except for a few casual words, and yet her name was like a summons to all my foolish blood. what is the general tone of the passage? a. courageous b. comical c. passionate d. fearful