Question

You, silent form, do tease us out of thought As does eternity: Cold Pastoral! When old age shall this generation waste, You shall remain, in the middle of other woe Than ours, a friend to man, to whom you say, “Beauty is truth, truth beauty,”—that is all You know on earth, and all you need to know. What is the poet saying when he writes that “old age shall this generation waste”? The poet is saying that people don’t live long; life is brief. The poet is saying that beauty is illusionary and short-lived. The poet is mourning the changes he sees in his “generation.” The poet is expressing his dread of growing older.

Answer 1

I am not 100% sure, although I feel the best answer to this question is A. The poet is saying that people don't live long; life is short.
This is because he talks about someone remaining, or living on. You can infer from this that the poet believes that life feels short and brief. The poet doesn't mention beauty in this line, nor foes he express changes in his generation. However, D is still a possible answer, but he doesn't focus as much on himself and his unwant to grow old. I hope that this can help you out! :D