Answer:
c Accidentally
Explanation:
According to the sentence given, Christopher Columbus had limited knowledge of world geography and inaccurate navigational devices; and as a result of this, he was able to accidentally discover North America and all the available riches there.
The word "inadvertently" as used in the sentence means accidentally.
Usually they are bigger and better than most normal humans but some have their flaws that make them more "likeable"
It's Rebuff
since reboof and rebaff are not words