Answer:
B. A PEACEFUL LABOR RALLY ENDED WITH A BOMB EXPLODING
 
        
             
        
        
        
Golly this one sure is hard. It eliminated the need for mail to be carried via roads or rail lines, and things (and people) could be carried directly to the destination's nearest airport instead of all the way down the winding roads to it. 
        
             
        
        
        
I think Vassal 
Definition of Vassal <span>- </span><span>A person who received a grant of land from a lord in exchange for a pledge of loyalty and services</span>
        
                    
             
        
        
        
They both have the same currency