Answer:
In ancient times, Nubia was the principal corridor where "there were cultural influences transmitted" between Black Africa and the Mediterranean basin.
Option B is the the right tense of this sentence correction task "b. through which cultural influences were transmitted".
Explanation:
 
        
             
        
        
        
Does it have to be 100 words or just the parentheses <span />
        
             
        
        
        
I believe this an example of complex sentence structure.
My reasoning is that most of these sentences are in fact compound complex sentences- 
Compound-complex sentences contain two independent clauses and at least one dependent clause.
An example of a complex sentence is this: “I burned dinner but not the cake.”