Answer:
C
threw tea into the harbor (about 342 if i remember correctly :3)
The middle class was different after the industrial revolution than it was before because prior to the Industrial Revolution, Europe had a small middle class. Following the Industrial Revolution, the middle class greatly grew.
After the industrial revolution, the lower classes were been able to "rise up" economically by getting new jobs in factories, thus much of the lower class entered the middle class.
The Limpopo river separates Botswana and South Africa
