Why did the writer add brackets to the sample sentence?
a. brackets set off the key word in the sentence.
b. brackets take up the least amount of space.
c. commas would work better in this sentence.
d. brackets allow the writer to change the verb tense of "add" so that it is consistent with the other verb tense in the sentence.?

Read the passage 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 norway gazed down upon the world from it’s 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? which identifies the textual evidence that best supports the claim: the authors purpose is to persuade? a: the author shares historical information about the wright brothers. b: the author states that men have walked the moon. c: the author states that others who think your dreams are impossible are wrong. d: the author wants to know what tasks we cannot accomplish.