Failure allows you to learn that making mistakes is contrary for you to learn how to avoid making mistakes like that again. You can't avoid something if you don't even know where it's coming from, so you need to make the mistake of not avoiding it to know how to avoid it next time.
The poem speaks of a giant statue of a great and well-renowned king, but that statue lies destroyed in the sand. It speaks of the king being so famous that even "the mighty" cannot compare with it. And yet, in an ironic twist, this statue is described as a wreck. This implies that death overpowers even great fame and wealth, and the best choice is A.