With the industrial revolution, which of the following would be most obsolete?
the skilled worker
the mechanic
the hand laborer
the inventor

In the Industrial Revolution, I think the answer is the hand laborer.

Most of the process in production can be done with machines so the hand laborers are replaced. Skilled laborers are still needed to maintain the quality of the products. Mechanic laborers are in demand to see that the machines in production will work properly. The inventor is needed to invent more machines to mechanize the production of goods.