The best answer is B.
Steam power technology developed slowly over a period of a few centuries. It reached practical application at the begining of the industrial revolution. The steam engine, a simple device that used boiling water to create mechanical motion that could be utilized in various kinds of useful work, was one of the most important technologies of the industrial revolution
Before that, water power in rivers or streams was used to operate mills. But this was prone to many setbacks because mills had to be located next to running water and also in winter the water would freeze and operations would stop. But a factory using a steam engine could be located anywhere and could run the whole year round.
