The sentences from the excerpt contribute to the text because they introduce the idea that Bob Heft has a legitimate place in American history. (option B)
According to the excerpt we are analyzing here, Bob Heft, a 17-year-old high school student, has a legitimate place in American history. The word "legitimate" implies that his story is a fact rather than a legend.
It is a fact that Heft was the one to design the American flag as we know it, whereas the story concerning Betsy Ross is most likely just a legend. Heft's flag was accepted by the Congress once Alaska and Hawaii were admitted as states.
With the information above in mind, we can choose letter B as the correct option.
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