The steam engine was crucial to Great Britain's Industrial Revolution. The answer to your question is D. I hope that this is the answer that you were looking for and it has helped you.
This answer depends greatly on the time period in question, but generally speaking it is true that the presence of many rivers and mountains protected China from invaders, and allowed their culture to grow with little outside influence, with the exception of Mongolian invasions from the north.
The groups that have historically been opposed to progressive reform in the United States have been the wealthy and elite, since this reform usually entails "spreading out the wealth" from the upper classes to the lower classes in various forms.
