Can someone tell me what this means?

However, the idea of real-life people living in what would become the united states for thousands of years before columbus ever left spain never dawned on me. what would be the best way to revise this sentence for greater clarity? a) however, the fact that columbus left spain thousands of years after people settled what would become the united states never dawned on me. b) it never dawned on me, however, the idea of real-life people living in what would become the united states for thousands of years before columbus ever left spain. c) however, the fact that people were already living in what would become the united states for thousands of years before columbus ever left spain never dawned on me. d) however, the idea never dawned on me that long before columbus ever left spain, real-life people lived for thousands of years in what would become the united states.

You suspect that this article has left out some facts that might lead the reader to believe that someone else made the star-spangled banner. what is the best way to verify this? by consulting a variety of sources by disregarding the article entirely by writing a letter to the editor of the publication that printed the article by reading various historical accounts by verifying the opinions

3. what is the purpose of a lead sentence or paragraph? to display your most convincing reasons and arguments to you revise the overall structure of your work to interest readers and introduce your writing style to add details and elaborate on your ideas