25 POINTS! urgent! answer with full explanation please, and quickly <3

Read this essay. First of all, if someone says your dream is impossible, they’re wrong. You can’t prove that something is impossible—all you know is that [it] hasn’t been done yet. People said no one could scale Mount Everest, but in 1953, Sir Edmund Hilary and Tenzing Norgay gazed down upon the world from its summit. People said that man could not fly, but in 1903, Orville and Wilbur Wright made the first sustained powered flight in a heavier-than-air machine. People said, “Okay, we admit that someone could climb Mount Everest, and we admit that man has learned to fly, but no one will ever, ever walk on the face of the moon.” If we can send three men a quarter of a million miles away and bring them home safely, is there any great task we cannot accomplish?

What is the best clue that the organizational structure of this essay is order of importance?

the fact that the author includes more than one piece of factual information

the fact that it contains a rhetorical question

the fact that the author urges the reader to not listen to other people

the fact that the passage begins with the transitional phrase "first of all"