It allowed the transportation of goods to be more efficient and quicker
B. is the answer you will want to put. While they did let African Americans fight in the war in a special unit, they would not allow that unit to be led by an African American. It was headed by a white man named Robert Gould Shaw.
The answer would be :
"<span>Their connections to trade brought wealth that spurred the Renaissance and spread new ideas. The competition among city-states encouraged new ways of thinking."
Hope this helps !
Photon</span>