What is the best definition of automation?

1) Automation is replacing human workers with mechanical or electronic devices.

2) Automation is applying scientific knowledge to find answers and fix problems.

3) Automation is using more resources to manufacture goods more efficiently.

4) Automation is hiring workers from all over the world to manufacture goods.

I believe the answer is: 1) Automation is replacing human workers with mechanical or electronic devices.

According to most economic experts, automation seems to be unavoidable and would create several economic advantages or disadvantages.

One advantage is that it would reduce the cost of production that would make products become cheaper, and one disadvantage of automation is that it would cause a huge number of unemployment.