I think it's the telephone because it allows people to communicate better and customers or workers don't have to walk up to everyone and disturb them. You may elaborate more on this with your own opinion
A. a disagreement between the states over representation in Congress
B. The National Assembly. This group dismantled the monarchy and in fall through spring of 1793-4, set about what would be called "The Reign of Terror", the bloodiest and most violent period of the French Revolution. The was led by Maximilien Robespierre and his associated Committee of Public Safety.