If you are fluent in two languages does it mean that you are bilanguage or you master two languages?

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.

Why might a reader look for an idea that is restated? to craft a summary of the article to find the subheadings in the article to identify the article's main idea to locate the article's key support

Which is these is not a benefit of parallel structure? a)clarity b)classification c)emphasis d)balance