Which word best illustrates the mood of the poem?

nothing gold can stay
by robert frost

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.

Hello

This might be a more opinionated question.. but I can try to answer it

I personally think the best word for this poem is "change".

It talks about how beauitiful everything is and then how it changes, expressed by "But only so an hour." It changes into grief, and finishes with "Nothing gold can stay."

I hope this helps!

Have a great day!