I already answered this for you. It's Persian messengers.
I believe the answer is: E. Anaconda Plan
Through the anaconda plan, the union planned to block out the southern ports in order to cut out the confederates' food and weaponaries supply.
This would reduce both the will power and millitary power of the confederates which help the union army to obtain early boost in the civil war.<span />
He made new sailing and navigating techniques, which made travel by boat much easier for the Europeans. But, on that note, his voyage to the new land forced Native Americans off of their land, and some of them into slavery. Columbus was violent and aggressive towards them in order to create what is now known as America.
Hope this helps a little bit