The answer is B) Economies shifted from being on manual labor to being driven by mass production.
With the advent of Machines and the Industrial Revolution, it was possible for Steam Engines and Textile Mills to get the same amount of production from 5 times less labor.
It also meant that everyday products such as textile, soap manufacturing, iron production etc could be mass produced, while earlier, this was not possible.
Mass production significantly increased the supply of goods, making them cheaper and improving their quality.
This led to a slight dip in employment early on, but as the economy grew and exports increased, more and more jobs were created in these new factories.