What made the transition from one-at-a-time manufacturing to mass production possible?
discovery of coal
building of factories
child labor laws
new technology

Let me help you out the answer is:

New Technology

Explanation: the answer is right there when you read the first paragraph of the lesson let me show you:

CALVERT ACADEMY- The Industrial Revolution is marked by a change in production from making things one-at-a-time by hand to making hundreds of items at a time by machines. This shift was made possible by the development of new technology.

there is my evidence to back up my answer hope this helped I know I'm really late...

affirmative action refers to the policies that take gender, race, or ethnicity into account in order to promote equal opportunity.

employers subject to title vii are prohibited from taking race or sex into account in any employment decisions. aa is a penalty for having any job group substantially statistically "underutilized" in any race or either sex. the employer must take steps to eliminate the underutilization, then stop, ending its aa efforts