Question

Which sentence from the passage supports the idea that the "world is chiefly indebted" to James Watt and George Stephenson for developing the steam engine?

Answer 1

If these were the missing choices: 

A. The first train consisted of thirty-four cars weighing, all told, ninety tons.
B. Before the time of Watt, the steam engine was exclusively a steam pump—slow and wasteful of fuel.
C. The idea of using steam for driving stationary machinery originated in the early centuries.
D. Watt made it a quick, powerful, and efficient engine, requiring only a fourth as much fuel as before.

My answer is D. WATT MADE IT A QUICK, POWERFUL, AND EFFICIENT ENGINE, REQUIRING ONLY A FOURTH AS MUCH FUEL AS BEFORE.

Though the passage is not given, I chose option D because it gives the benefit that others experienced from Watt's contribution.