(B) Rather than accepting the conventional wisdom that the earth was flat, Christopher Columbus was sent by the king and queen of Spain to see if he could reach India by sailing west.
There are flaws in B, the most significant of them that the sentence starts with Rather than accepting and then goes into Christopher Columbus was sent by the king and queen.
So accepting, something the sentence conveys the Christopher Columbus didn't do, is essentially compared to sent, which is something the king and queen did.
You need Christopher Columbus himself to do one thing rather than another.
You can find that type of comparison in the correct answer, which is D.
