This map shows several Trans-Saharan trade routes, which flourished between 600 and 1450. The map best supports the idea that

A.
Africans had little interest in exploring outside of Africa.
B.
peoples across Northern Africa were in contact with one another.
C.
Africans struggled to find a way to cross the Sahara desert.
D.
Northern Africa was divided into distinct kingdoms.

B. peoples across Northern Africa were in contact with one another.